urbanAtomic Exception

Exception Type: Error
Occurance: /var/www/vhosts/drg.de/httpdocs/site/inc/mysqlcompat.php in Line 72

Call Stack :
#0 /var/www/vhosts/drg.de/httpdocs/site/inc/mysqlcompat.php(72): mysqli->select_db()
#1 /var/www/vhosts/drg.de/httpdocs/site/inc/classes/ua/db.php(36): mysql_select_db()
#2 /var/www/vhosts/drg.de/httpdocs/site/inc/classes/ua.php(94): ua_db->__construct()
#3 /var/www/vhosts/drg.de/httpdocs/site/inc/classes/ua.php(46): ua->instantiate()
#4 /var/www/vhosts/drg.de/httpdocs/site/inc/config.inc.php(30): ua::init()
#5 /var/www/vhosts/drg.de/httpdocs/site/index.php(68): require_once('...')
#6 {main}

Error Message: mysqli object is already closed