SQL-DATABASE ERROR

Database error in WoltLab Burning Board (): Link-ID == false, connect failed
mysql error: Too many connections
mysql error number: 1040
mysql version: unknown
php version: 5.4.45
Date: 23.04.2018 @ 03:41
Script: /usercp.php?action=addsubscription&boardid=26&sid=9788438b2b6f2b1fc8c29176223e78c4
Referer: