After upgrade 20.0.7 Dav error

Nextcloud version 20.0.7
PRETTY_NAME=“Raspbian GNU/Linux 10 (buster)”
Server version: Apache/2.4.38 (Raspbian)
PHP 7.3.19-1~deb10u1 (cli) (built: Jul 5 2020 06:46:45) ( NTS

After upgrade got error : Sabre\DAV\Exception\ServiceUnavailable: Could not open file

Is this the first time you’ve seen this error.YES

The output of your Nextcloud log in Admin > Logging:

	Sabre\DAV\Exception\ServiceUnavailable: Could not open file

    /var/www/html/nextcloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php - line 90:

    OCA\DAV\Connector\Sabre\File->get()

    /var/www/html/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php - line 89:

    Sabre\DAV\CorePlugin->httpGet(Sabre\HTTP\Request {}, Sabre\HTTP\Response {})

    /var/www/html/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 474:

    Sabre\DAV\Server->emit("method:GET", [ Sabre\HTTP ... }])

    /var/www/html/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 251:

    Sabre\DAV\Server->invokeMethod(Sabre\HTTP\Request {}, Sabre\HTTP\Response {})

    /var/www/html/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 319:

    Sabre\DAV\Server->start()

    /var/www/html/nextcloud/apps/dav/lib/Server.php - line 332:

    Sabre\DAV\Server->exec()

    /var/www/html/nextcloud/apps/dav/appinfo/v2/remote.php - line 35:

    OCA\DAV\Server->exec()

    /var/www/html/nextcloud/remote.php - line 167:

    require_once("/var/www/ht ... p")

The output of your config.php file in `/path/to/nextcloud

<?php
$CONFIG = array (
  'instanceid' => 'ocq672tongwu',
  'passwordsalt' => 'xxxxxxxxxxxxxxx',
  'secret' => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
  'trusted_domains' => 
  array (
    0 => '213.xxx.xxx.xxx',
    1 => '192.168.31.232',
  ),
  'datadirectory' => '/mnt/hdd/nextcloud/data',
  'dbtype' => 'mysql',
  'version' => '20.0.7.1',
  'overwrite.cli.url' => 'https://xxx.xxx.xxx.xxx/nextcloud',
  'dbname' => 'nextcloud',
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => '',
  'dbpassword' => '',
  'installed' => true,
  'app_install_overwrite' => 
  array (
    0 => 'twofactor_rcdevsopenotp',
  ),
  'twofactor_enforced' => 'true',
  'twofactor_enforced_groups' => 
  array (
    0 => 'admin',
  ),
  'twofactor_enforced_excluded_groups' => 
  array (
  ),
  'mail_smtpmode' => 'smtp',
  'mail_smtpsecure' => 'ssl',
  'mail_sendmailmode' => 'smtp',
  'mail_smtpauthtype' => 'LOGIN',
  'maintenance' => false,
  'theme' => '',
  'loglevel' => 3,
  'has_rebuilt_cache' => true,
  'encryption.legacy_format_support' => false,
  'encryption.key_storage_migrated' => false,
);


var/log/apache:

192.168.31.1 - donatanc [16/Feb/2021:00:16:54 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5166 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:00:16:54 +0200] “PROPFIND /nextcloud/remote.php/dav/addressbooks/users/donatanc/contacts/ HTTP/1.1” 207 5063 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:00:16:57 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/personal/ HTTP/1.1” 207 5161 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; o$
192.168.31.1 - donatanc [16/Feb/2021:00:39:25 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5029 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
23.129.64.226 - - [16/Feb/2021:00:41:25 +0200] “GET / HTTP/1.1” 403 3244 “-” “Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)”
192.168.31.1 - donatanc [16/Feb/2021:01:06:15 +0200] “PROPFIND /nextcloud/remote.php/dav/addressbooks/users/donatanc/contacts/ HTTP/1.1” 207 5059 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
138.68.73.41 - - [16/Feb/2021:01:09:59 +0200] “GET / HTTP/1.1” 403 2868 “-” “curl/7.58.0”
170.130.187.58 - - [16/Feb/2021:01:53:37 +0200] “GET / HTTP/1.1” 403 2689 “-” “https://gdnplus.com:Gather Analyze Provide.”
50.116.36.25 - - [16/Feb/2021:02:08:54 +0200] “GET / HTTP/1.1” 403 2689 “-” "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Sa$
192.168.31.1 - donatanc [16/Feb/2021:02:38:06 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5027 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
192.168.31.1 - donatanc [16/Feb/2021:02:38:06 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5170 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:02:38:06 +0200] “PROPFIND /nextcloud/remote.php/dav/addressbooks/users/donatanc/contacts/ HTTP/1.1” 207 5063 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:02:38:09 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5031 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
192.168.31.1 - donatanc [16/Feb/2021:02:38:10 +0200] “PROPFIND /nextcloud/remote.php/dav/addressbooks/users/donatanc/contacts/ HTTP/1.1” 207 5069 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:02:38:11 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5176 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:02:38:11 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/personal/ HTTP/1.1” 207 5167 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; o$
39.107.178.184 - - [16/Feb/2021:02:42:45 +0200] “GET / HTTP/1.1” 403 3244 “-” “Go-http-client/1.1”
192.168.31.1 - donatanc [16/Feb/2021:03:49:57 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5172 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:03:49:57 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5035 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
192.168.31.1 - donatanc [16/Feb/2021:03:50:00 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/personal/ HTTP/1.1” 207 5163 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; o$
167.71.175.10 - - [16/Feb/2021:04:13:35 +0200] “GET / HTTP/1.1” 403 3273 “-” “curl/7.58.0”
184.105.247.252 - - [16/Feb/2021:05:36:11 +0200] “GET / HTTP/1.1” 403 2689 “-” “-”
192.168.31.1 - donatanc [16/Feb/2021:06:28:34 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5168 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:06:28:34 +0200] “PROPFIND /nextcloud/remote.php/dav/addressbooks/users/donatanc/contacts/ HTTP/1.1” 207 5059 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:06:28:36 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/personal/ HTTP/1.1” 207 5161 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; o$
192.168.31.1 - donatanc [16/Feb/2021:06:28:34 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5031 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
34.78.227.165 - - [16/Feb/2021:06:51:03 +0200] “GET / HTTP/1.1” 403 2760 “-” “python-requests/2.25.1”
193.118.53.202 - - [16/Feb/2021:07:18:35 +0200] “GET / HTTP/1.1” 403 2689 “-” "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 $
192.168.31.1 - donatanc [16/Feb/2021:07:38:32 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5029 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
192.168.31.1 - donatanc [16/Feb/2021:07:38:32 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5170 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:07:38:34 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/personal/ HTTP/1.1” 207 5157 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; o$
192.168.31.1 - donatanc [16/Feb/2021:08:06:06 +0200] “PROPFIND /nextcloud/remote.php/dav/addressbooks/users/donatanc/contacts/ HTTP/1.1” 207 5065 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
97.74.229.113 - - [16/Feb/2021:08:40:52 +0200] “GET /admin//config.php HTTP/1.1” 404 2653 “-” "curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18$
192.168.31.1 - donatanc [16/Feb/2021:09:01:04 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/tasks/ HTTP/1.1” 207 5029 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm; okht$
192.168.31.1 - donatanc [16/Feb/2021:09:01:05 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/contact_birthdays/ HTTP/1.1” 207 5172 “-” "DAVx5/2.6.4-ose (2020/02/28; d$
192.168.31.1 - donatanc [16/Feb/2021:09:01:07 +0200] “PROPFIND /nextcloud/remote.php/dav/calendars/donatanc/personal/ HTTP/1.1” 207 5159 “-” "DAVx5/2.6.4-ose (2020/02/28; dav4jvm;:

Looks like a permission problem. Can you show the permissions of this file (and folder):

require_once("/var/www/ht ... p")

do a ls -lisa /path/to/folder

8921647 4 drwxr-xr-x 14 www-data www-data 4096 Feb 4 08:39 nextcloud