LDAP / AD Error after Update to 11.0.2

Nextcloud version 11.0.2.7
Operating system and version Debian 8.7
Apache version 2.4.10
PHP version 5.6
LDAP user and group backend 1.1.2
LDAP Windows Server 2012R2

After Update from 11.0.1 the Login via LDAP produces errors, they get “An internal server error occurred. Please try again later.”. Local Users are able to login.

In the nextcloud Log:
“Login failed: ‘xyz’ (Remote IP: ‘10.0.0.240’)”,“level”:2,“time”:“2017-03-22T08:11:11+00:00”,“method”:“OPTIONS”,“url”:"/remote.php/webdav",“user”:"–",“version”:“11.0.2.7”}
“user_ldap”,“message”:“Configuration Error (prefix ): either no password is given for theuser agent or a password is given, but not anLDAP agent.”,“level”:2,“time”:“2017-03-22T08:18:56+00:00”,“method”:“OPTIONS”,“url”:"/remote.php/webdav",“user”:"–",“version”:“11.0.2.7”}

I checked the LDAP Configuration and everything is green there, tests are successful. After deleting the LDAP Server and re-adding it, it works for a few login at the webinterface. But then it fails again with the same error.

The config.php:

<?php $CONFIG = array ( 'instanceid' => 'xxxx', 'passwordsalt' => 'xxxx', 'datadirectory' => '/mnt/cloud', 'dbtype' => 'mysql', 'version' => '11.0.2.7', 'dbname' => 'owncloud', 'dbhost' => 'localhost', 'dbtableprefix' => 'oc_', 'dbuser' => 'www-data', 'dbpassword' => 'xxx', 'installed' => true, 'forcessl' => true, 'overwriteprotocol' => 'https', 'theme' => 'W9', 'default_language' => 'en', 'maintenance' => false, 'ldapIgnoreNamingRules' => false, 'maxZipInputSize' => 17179869184, 'allowZipDownload' => true, 'proxy' => 'xxx:3128', 'trusted_domains' => array ( 0 => 'xxx.xxx.xx', 1 => 'owncloud', 'loglevel' => 2, 'mail_smtpdebug' => true, 'mail_smtpmode' => 'smtp', 'mail_from_address' => 'xx', 'mail_domain' => 'xxx', 'mail_smtphost' => 'xxx', 'mail_smtpport' => '25', 'secret' => 'xxxx', 'appstore.experimental.enabled' => false, 'trashbin_retention_obligation' => 'auto', 'updatechecker' => false, 'htaccess.RewriteBase' => '/', 'ldapProviderFactory' => '\\OCA\\User_LDAP\\LDAPProviderFactory', 'updater.release.channel' => 'stable', 'memcache.local' => '\\OC\\Memcache\\APCu', );