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: 5.6.40-53+0~20210826.55+debian9~1.gbp975ea4
Date: 08.12.2022 @ 03:12
Script: /register.php?sid=f36787c5a3763114d0404f3590ebd09f
Referer: