Database error in vBulletin :

mysql_connect(): Can't connect to MySQL server on 'mysqlucoolbbsmaster' (104)
/data/product/ucool/production/bbs/a/includes/class_core.php on line 317

MySQL Error   : 
Error Number  : 
Request Date  : Sunday, December 3rd 2023 @ 06:21:20 PM
Error Date    : Sunday, December 3rd 2023 @ 06:21:28 PM
Script        : http://forum.ucool.com/member.php?113500-oatlovemvk40-gmail-com&tab=activitystream&type=all
Referrer      : 
IP Address    : 3.239.2.192
Username      : 
Classname     : vB_Database
MySQL Version :