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 @ 03:54
Script: /register.php?sid=21c0f70f92ec6c8fc10ce7dd1c7d40bd
Referer: