After fresh install change of admin password and adding new user not possible

I made a fresh installation, using the setup-nextcloud.php installer on my Webspace hosted by http://alfahosting.de/. Afterwards I wasn’t either able to change the admin password nor to add a new user.

Server configuration

Operating system:
Linux

Web server:
unknown

Database:
mysql 5.7

PHP version:
php7.1
Signing status:

Signing status
Results
=======
- core
	- INVALID_HASH
		- .htaccess
	- EXTRA_FILE
		- setup-nextcloud.php
Raw output
==========
Array
(
    [core] => Array
        (
            [INVALID_HASH] => Array
                (
                    [.htaccess] => Array
                        (
                            [expected] => 11e2db30f0cf23df1b5aa1cdf329a8c88d253f86e43f9e7af1b30969eb0175030103b138e2f7ab7608c902bbb57a5d578c2c0ca09f3abf2ef83415f4bc6f6e20
                            [current] => bbc420743075c824c8beca7e4cda7add816566463b7160b7575d2504d3439a733151307f8b9d172cac80da85be4cef44c2f89506288ae4a49b867d1f8b8c441e
                        )

                )

            [EXTRA_FILE] => Array
                (
                    [setup-nextcloud.php] => Array
                        (
                            [expected] => 
                            [current] => 28c87f7f7084e35e87a48aec1d13b14d322dcd6fa0c862f7ba07bc5408c5772b34c66d5b5cb6f85dbbc0965e1e7858be8598a8795229d8b7c2b4ba2093d8d14d
                        )

                )

        )

)

The diff hash of .htaccess is because I had to activate php7.1 via htaccess.

List of activated apps:
just Default apps acticvated

The content of config/config.php:

Config report
<?php
$CONFIG = array (
  'instanceid' => 'oc6llg9spyqb',
  'passwordsalt' => ,
  'secret' => ,
  'trusted_domains' => 
  array (
    0 => 'wolke.dpsg-bodensee.de',
  ),
  'datadirectory' => '/var/www/web1519/html/nextcloud/data',
  'overwrite.cli.url' => 'http://wolke.dpsg-bodensee.de',
  'dbtype' => 'mysql',
  'version' => '11.0.0.10',
  'dbname' => 'xxx',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'web1519',
  'dbpassword' => ,
  'logtimezone' => 'UTC',
  'installed' => true,
);

Are you using external storage, if yes which one: local/smb/sftp/…
no

Are you using encryption: yes/no
yes

Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/…
no

Nextcloud log (data/nextcloud.log)

Nextcloud log
{"reqId":"zyMk\/vH0JltZAcPtxrpK","remoteAddr":"92.217.26.159","app":"PHP","message":"Allowed memory size of 20971520 bytes exhausted (tried to allocate 528384 bytes) at \/var\/www\/web1519\/html\/nextcloud\/apps\/password_policy\/lists\/list-8.php#62562","level":3,"time":"2017-03-26T18:15:02+00:00","method":"POST","url":"\/index.php\/settings\/personal\/changepassword","user":"stefan","version":"11.0.0.10"}
{"reqId":"5ZR+7yOBcfnKyY5MZDkp","remoteAddr":"92.217.26.159","app":"core","message":"Login failed: 'stefan' (Remote IP: '92.217.26.159')","level":2,"time":"2017-03-26T18:15:30+00:00","method":"PROPFIND","url":"\/remote.php\/webdav\/","user":"--","version":"11.0.0.10"}
{"reqId":"mcs6202lTg4znKyDeGwy","remoteAddr":"92.217.26.159","app":"core","message":"Login failed: 'stefan' (Remote IP: '92.217.26.159')","level":2,"time":"2017-03-26T18:15:47+00:00","method":"PROPFIND","url":"\/remote.php\/webdav\/","user":"--","version":"11.0.0.10"}
{"reqId":"pogE69Gk6MKK7rAX5ETq","remoteAddr":"92.217.26.159","app":"PHP","message":"Allowed memory size of 20971520 bytes exhausted (tried to allocate 528384 bytes) at \/var\/www\/web1519\/html\/nextcloud\/apps\/password_policy\/lists\/list-8.php#62562","level":3,"time":"2017-03-26T18:28:43+00:00","method":"POST","url":"\/index.php\/settings\/personal\/changepassword","user":"stefan","version":"11.0.0.10"}
{"reqId":"4wi7DU\/aa7Eun3wieSeW","remoteAddr":"92.217.26.159","app":"PHP","message":"Allowed memory size of 20971520 bytes exhausted (tried to allocate 528384 bytes) at \/var\/www\/web1519\/html\/nextcloud\/apps\/password_policy\/lists\/list-8.php#62562","level":3,"time":"2017-03-26T18:30:55+00:00","method":"POST","url":"\/index.php\/settings\/personal\/changepassword","user":"stefan","version":"11.0.0.10"}
{"reqId":"HwSI3N6RnEARxKeCAaiv","remoteAddr":"92.217.26.159","app":"PHP","message":"Allowed memory size of 20971520 bytes exhausted (tried to allocate 528384 bytes) at \/var\/www\/web1519\/html\/nextcloud\/apps\/password_policy\/lists\/list-8.php#62562","level":3,"time":"2017-03-26T18:34:22+00:00","method":"POST","url":"\/index.php\/settings\/personal\/changepassword","user":"stefan","version":"11.0.0.10"}
{"reqId":"pA4tBd5zpH1xtlLJDAZh","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:35:44+00:00","method":"GET","url":"\/index.php\/settings\/ajax\/checksetup","user":"admin","version":"11.0.0.10"}
{"reqId":"xo6q1b4ldl879b1\/14w3","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:43:54+00:00","method":"GET","url":"\/index.php\/apps\/systemtags\/lastused","user":"admin","version":"11.0.0.10"}
{"reqId":"H99asLdcTXhJMRrINLLG","remoteAddr":"92.217.26.159","app":"PHP","message":"Allowed memory size of 20971520 bytes exhausted (tried to allocate 528384 bytes) at \/var\/www\/web1519\/html\/nextcloud\/apps\/password_policy\/lists\/list-8.php#50646","level":3,"time":"2017-03-26T18:44:27+00:00","method":"POST","url":"\/index.php\/settings\/users\/changepassword","user":"admin","version":"11.0.0.10"}
{"reqId":"YceKWorq72y0bgmlljuw","remoteAddr":"92.217.26.159","app":"PHP","message":"Allowed memory size of 20971520 bytes exhausted (tried to allocate 4718592 bytes) at \/var\/www\/web1519\/html\/nextcloud\/apps\/password_policy\/lists\/list-9.php#3","level":3,"time":"2017-03-26T18:44:33+00:00","method":"POST","url":"\/index.php\/settings\/users\/changepassword","user":"admin","version":"11.0.0.10"}
{"reqId":"npSaaKaOZC3zSXjxl\/Ac","remoteAddr":"92.217.26.159","app":"core","message":"Login failed: 'admin' (Remote IP: '92.217.26.159')","level":2,"time":"2017-03-26T18:45:19+00:00","method":"POST","url":"\/index.php\/login","user":"--","version":"11.0.0.10"}
{"reqId":"OhNgRQdQJJiFy7DAf5Mu","remoteAddr":"92.217.26.159","app":"core","message":"Login failed: 'admin' (Remote IP: '92.217.26.159')","level":2,"time":"2017-03-26T18:45:52+00:00","method":"POST","url":"\/index.php\/login?user=admin","user":"--","version":"11.0.0.10"}
{"reqId":"nzOIKecs7NpyX9Y3+adz","remoteAddr":"92.217.26.159","app":"core","message":"Login failed: 'stefan' (Remote IP: '92.217.26.159')","level":2,"time":"2017-03-26T18:48:18+00:00","method":"PROPFIND","url":"\/remote.php\/webdav\/","user":"--","version":"11.0.0.10"}
{"reqId":"8N6yykwfa7r4vNtNxUhq","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:50:29+00:00","method":"PUT","url":"\/remote.php\/dav\/files\/stefan\/Homepage\/README.txt","user":"stefan","version":"11.0.0.10"}
{"reqId":"rtNAM8ZpJ4AOwC7Bk2i5","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:50:33+00:00","method":"PUT","url":"\/remote.php\/dav\/files\/stefan\/Homepage\/web.config.txt","user":"stefan","version":"11.0.0.10"}
{"reqId":"baYV+OvxKYtbm\/himYzO","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:50:34+00:00","method":"PUT","url":"\/remote.php\/dav\/files\/stefan\/Homepage\/templates\/atomic\/css\/index.html","user":"stefan","version":"11.0.0.10"}
{"reqId":"LlH1l8GSJvsUtoV+KEgz","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:50:37+00:00","method":"PUT","url":"\/remote.php\/dav\/files\/stefan\/Homepage\/templates\/atomic\/css\/blueprint\/print.css","user":"stefan","version":"11.0.0.10"}
{"reqId":"droDXMVubBN2+opPuKh3","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T18:50:56+00:00","method":"PUT","url":"\/remote.php\/dav\/files\/stefan\/Homepage\/templates\/atomic\/templateDetails.xml","user":"stefan","version":"11.0.0.10"}
{"reqId":"bJCZVmfml9hgs5sgEktj","remoteAddr":"92.217.26.159","app":"webdav","message":"Exception: {\"Message\":\"HTTP\\\/1.1 415 Validation error in vCard: The supplied value (27) is not a correct DATE-AND-OR-TIME property\",\"Exception\":\"Sabre\\\\DAV\\\\Exception\\\\UnsupportedMediaType\",\"Code\":0,\"Trace\":\"#0 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php(294): Sabre\\\\CardDAV\\\\Plugin->validateVCard('BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#1 [internal function]: Sabre\\\\CardDAV\\\\Plugin->beforeWriteContent('addressbooks\\\/us...', Object(Sabre\\\\CardDAV\\\\Card), 'BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#2 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#3 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(1104): Sabre\\\\Event\\\\EventEmitter->emit('beforeWriteCont...', Array)\\n#4 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/CorePlugin.php(513): Sabre\\\\DAV\\\\Server->updateFile('addressbooks\\\/us...', 'BEGIN:VCARD\\\\r\\\\nVE...', NULL)\\n#5 [internal function]: Sabre\\\\DAV\\\\CorePlugin->httpPut(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#6 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#7 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(479): Sabre\\\\Event\\\\EventEmitter->emit('method:PUT', Array)\\n#8 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(254): Sabre\\\\DAV\\\\Server->invokeMethod(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#9 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/lib\\\/Server.php(227): Sabre\\\\DAV\\\\Server->exec()\\n#10 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/appinfo\\\/v2\\\/remote.php(30): OCA\\\\DAV\\\\Server->exec()\\n#11 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/remote.php(165): require_once('\\\/var\\\/www\\\/web151...')\\n#12 {main}\",\"File\":\"\\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php\",\"Line\":397,\"User\":\"stefan\"}","level":4,"time":"2017-03-26T19:15:03+00:00","method":"PUT","url":"\/remote.php\/dav\/addressbooks\/users\/stefan\/BL\/cbefb82d-fc2d-4183-9365-1df421d09dec.vcf","user":"stefan","version":"11.0.0.10"}
{"reqId":"ibgR8TrrGac5C\/u5Pds9","remoteAddr":"92.217.26.159","app":"webdav","message":"Exception: {\"Message\":\"HTTP\\\/1.1 415 Validation error in vCard: The supplied value (279) is not a correct DATE-AND-OR-TIME property\",\"Exception\":\"Sabre\\\\DAV\\\\Exception\\\\UnsupportedMediaType\",\"Code\":0,\"Trace\":\"#0 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php(294): Sabre\\\\CardDAV\\\\Plugin->validateVCard('BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#1 [internal function]: Sabre\\\\CardDAV\\\\Plugin->beforeWriteContent('addressbooks\\\/us...', Object(Sabre\\\\CardDAV\\\\Card), 'BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#2 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#3 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(1104): Sabre\\\\Event\\\\EventEmitter->emit('beforeWriteCont...', Array)\\n#4 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/CorePlugin.php(513): Sabre\\\\DAV\\\\Server->updateFile('addressbooks\\\/us...', 'BEGIN:VCARD\\\\r\\\\nVE...', NULL)\\n#5 [internal function]: Sabre\\\\DAV\\\\CorePlugin->httpPut(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#6 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#7 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(479): Sabre\\\\Event\\\\EventEmitter->emit('method:PUT', Array)\\n#8 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(254): Sabre\\\\DAV\\\\Server->invokeMethod(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#9 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/lib\\\/Server.php(227): Sabre\\\\DAV\\\\Server->exec()\\n#10 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/appinfo\\\/v2\\\/remote.php(30): OCA\\\\DAV\\\\Server->exec()\\n#11 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/remote.php(165): require_once('\\\/var\\\/www\\\/web151...')\\n#12 {main}\",\"File\":\"\\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php\",\"Line\":397,\"User\":\"stefan\"}","level":4,"time":"2017-03-26T19:15:03+00:00","method":"PUT","url":"\/remote.php\/dav\/addressbooks\/users\/stefan\/BL\/cbefb82d-fc2d-4183-9365-1df421d09dec.vcf","user":"stefan","version":"11.0.0.10"}
{"reqId":"VTRrlOZycjejnLNJZwTK","remoteAddr":"92.217.26.159","app":"webdav","message":"Exception: {\"Message\":\"HTTP\\\/1.1 415 Validation error in vCard: The supplied value (2791984) is not a correct DATE-AND-OR-TIME property\",\"Exception\":\"Sabre\\\\DAV\\\\Exception\\\\UnsupportedMediaType\",\"Code\":0,\"Trace\":\"#0 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php(294): Sabre\\\\CardDAV\\\\Plugin->validateVCard('BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#1 [internal function]: Sabre\\\\CardDAV\\\\Plugin->beforeWriteContent('addressbooks\\\/us...', Object(Sabre\\\\CardDAV\\\\Card), 'BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#2 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#3 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(1104): Sabre\\\\Event\\\\EventEmitter->emit('beforeWriteCont...', Array)\\n#4 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/CorePlugin.php(513): Sabre\\\\DAV\\\\Server->updateFile('addressbooks\\\/us...', 'BEGIN:VCARD\\\\r\\\\nVE...', NULL)\\n#5 [internal function]: Sabre\\\\DAV\\\\CorePlugin->httpPut(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#6 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#7 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(479): Sabre\\\\Event\\\\EventEmitter->emit('method:PUT', Array)\\n#8 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(254): Sabre\\\\DAV\\\\Server->invokeMethod(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#9 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/lib\\\/Server.php(227): Sabre\\\\DAV\\\\Server->exec()\\n#10 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/appinfo\\\/v2\\\/remote.php(30): OCA\\\\DAV\\\\Server->exec()\\n#11 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/remote.php(165): require_once('\\\/var\\\/www\\\/web151...')\\n#12 {main}\",\"File\":\"\\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php\",\"Line\":397,\"User\":\"stefan\"}","level":4,"time":"2017-03-26T19:15:05+00:00","method":"PUT","url":"\/remote.php\/dav\/addressbooks\/users\/stefan\/BL\/cbefb82d-fc2d-4183-9365-1df421d09dec.vcf","user":"stefan","version":"11.0.0.10"}
{"reqId":"cWKQsBu0rHoxHo2MWplH","remoteAddr":"92.217.26.159","app":"webdav","message":"Exception: {\"Message\":\"HTTP\\\/1.1 415 Validation error in vCard: The supplied value (27) is not a correct DATE-AND-OR-TIME property\",\"Exception\":\"Sabre\\\\DAV\\\\Exception\\\\UnsupportedMediaType\",\"Code\":0,\"Trace\":\"#0 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php(294): Sabre\\\\CardDAV\\\\Plugin->validateVCard('BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#1 [internal function]: Sabre\\\\CardDAV\\\\Plugin->beforeWriteContent('addressbooks\\\/us...', Object(Sabre\\\\CardDAV\\\\Card), 'BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#2 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#3 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(1104): Sabre\\\\Event\\\\EventEmitter->emit('beforeWriteCont...', Array)\\n#4 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/CorePlugin.php(513): Sabre\\\\DAV\\\\Server->updateFile('addressbooks\\\/us...', 'BEGIN:VCARD\\\\r\\\\nVE...', NULL)\\n#5 [internal function]: Sabre\\\\DAV\\\\CorePlugin->httpPut(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#6 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#7 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(479): Sabre\\\\Event\\\\EventEmitter->emit('method:PUT', Array)\\n#8 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(254): Sabre\\\\DAV\\\\Server->invokeMethod(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#9 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/lib\\\/Server.php(227): Sabre\\\\DAV\\\\Server->exec()\\n#10 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/appinfo\\\/v2\\\/remote.php(30): OCA\\\\DAV\\\\Server->exec()\\n#11 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/remote.php(165): require_once('\\\/var\\\/www\\\/web151...')\\n#12 {main}\",\"File\":\"\\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php\",\"Line\":397,\"User\":\"stefan\"}","level":4,"time":"2017-03-26T19:15:09+00:00","method":"PUT","url":"\/remote.php\/dav\/addressbooks\/users\/stefan\/BL\/cbefb82d-fc2d-4183-9365-1df421d09dec.vcf","user":"stefan","version":"11.0.0.10"}
{"reqId":"sMSzTV+GQ4shawEbEBAF","remoteAddr":"92.217.26.159","app":"PHP","message":"DateTime::__construct(): Failed to parse time string (1984-) at position 4 (-): Unexpected character at \/var\/www\/web1519\/html\/nextcloud\/apps\/dav\/lib\/CalDAV\/BirthdayService.php#148","level":3,"time":"2017-03-26T19:15:18+00:00","method":"PUT","url":"\/remote.php\/dav\/addressbooks\/users\/stefan\/BL\/cbefb82d-fc2d-4183-9365-1df421d09dec.vcf","user":"stefan","version":"11.0.0.10"}
{"reqId":"R44SenIYoqbzEgrYI2fB","remoteAddr":"92.217.26.159","app":"webdav","message":"Exception: {\"Message\":\"HTTP\\\/1.1 415 Validation error in vCard: The supplied value (1984-09-) is not a correct DATE-AND-OR-TIME property\",\"Exception\":\"Sabre\\\\DAV\\\\Exception\\\\UnsupportedMediaType\",\"Code\":0,\"Trace\":\"#0 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php(294): Sabre\\\\CardDAV\\\\Plugin->validateVCard('BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#1 [internal function]: Sabre\\\\CardDAV\\\\Plugin->beforeWriteContent('addressbooks\\\/us...', Object(Sabre\\\\CardDAV\\\\Card), 'BEGIN:VCARD\\\\r\\\\nVE...', false)\\n#2 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#3 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(1104): Sabre\\\\Event\\\\EventEmitter->emit('beforeWriteCont...', Array)\\n#4 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/CorePlugin.php(513): Sabre\\\\DAV\\\\Server->updateFile('addressbooks\\\/us...', 'BEGIN:VCARD\\\\r\\\\nVE...', NULL)\\n#5 [internal function]: Sabre\\\\DAV\\\\CorePlugin->httpPut(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#6 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/event\\\/lib\\\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\\n#7 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(479): Sabre\\\\Event\\\\EventEmitter->emit('method:PUT', Array)\\n#8 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/DAV\\\/Server.php(254): Sabre\\\\DAV\\\\Server->invokeMethod(Object(Sabre\\\\HTTP\\\\Request), Object(Sabre\\\\HTTP\\\\Response))\\n#9 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/lib\\\/Server.php(227): Sabre\\\\DAV\\\\Server->exec()\\n#10 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/apps\\\/dav\\\/appinfo\\\/v2\\\/remote.php(30): OCA\\\\DAV\\\\Server->exec()\\n#11 \\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/remote.php(165): require_once('\\\/var\\\/www\\\/web151...')\\n#12 {main}\",\"File\":\"\\\/var\\\/www\\\/web1519\\\/html\\\/nextcloud\\\/3rdparty\\\/sabre\\\/dav\\\/lib\\\/CardDAV\\\/Plugin.php\",\"Line\":397,\"User\":\"stefan\"}","level":4,"time":"2017-03-26T19:15:21+00:00","method":"PUT","url":"\/remote.php\/dav\/addressbooks\/users\/stefan\/BL\/cbefb82d-fc2d-4183-9365-1df421d09dec.vcf","user":"stefan","version":"11.0.0.10"}
{"reqId":"8eCw3KxhCiy2xXCBUeZW","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-26T19:50:03+00:00","method":"GET","url":"\/index.php\/apps\/systemtags\/lastused","user":"admin","version":"11.0.0.10"}
{"reqId":"2cjftHHEHsqlHv4gqYNB","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-27T02:12:10+00:00","method":"GET","url":"\/status.php","user":"--","version":"11.0.0.10"}
{"reqId":"rrDv9r\/rOsqnYLd73soY","remoteAddr":"92.217.26.159","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-27T02:15:03+00:00","method":"GET","url":"\/status.php","user":"--","version":"11.0.0.10"}
{"reqId":"RzGQ9XRHcPQwizxMjURr","remoteAddr":"212.62.213.98","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-27T11:10:54+00:00","method":"GET","url":"\/index.php","user":"--","version":"11.0.0.10"}
{"reqId":"wYBRK6Ab4pH+VldKJw30","remoteAddr":"212.62.213.98","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-27T11:10:54+00:00","method":"GET","url":"\/index.php","user":"--","version":"11.0.0.10"}
{"reqId":"d7p93MKrivTMbMd3WiAu","remoteAddr":"212.62.213.98","app":"PHP","message":"Directive 'allow_call_time_pass_reference' is no longer available in PHP 5.4 or newer at Unknown#0","level":3,"time":"2017-03-27T11:11:07+00:00","method":"GET","url":"\/index.php\/apps\/systemtags\/lastused","user":"admin","version":"11.0.0.10"}

This pops up in the logs several times, also related with password change attempt. There is only 20 MB memory allowed for you on the shared host, or is this only related to database or somehow a bug? I guess you should check that, ask your host in case.

thx. seems like this solved my problem.