Uncaught exception thrown in shutdown function.

PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database: DELETE FROM {semaphore} WHERE (value = :db_condition_placeholder_0) ; Array ( [:db_condition_placeholder_0] => 21275156525bcb4e09d17fd7.05920622 ) in lock_release_all() (line 266 of /var/www/vhosts/thai-masaza.si/httpdocs/includes/lock.inc).