Problem when update plugin group folder

Hi,
I have a problem. After updating the group folder plugin, I have a 503 server error and the message in the apache log:

[Wed Aug 08 10:06:48.408053 2018] [:error] [pid 3723] [client 172.21.83.18:50812] PHP Fatal error: Uncaught Doctrine\DBAL\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:61\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\DB\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\DBAL\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\DBAL\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\DBAL\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(148): Doctrine\DBAL\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\DB\Connection->__construct(Array, Object(Doctrine\DBAL\Driver\PDOMySql\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 61

  • installed: true
    • version: 12.0.5.3
    • versionstring: 12.0.5
    • edition:

Ubuntu 16.0.4, php7.0, mariadb.