mysql error

hello i have a client who use whm and cpanel also he has added a prestashop website to his panel but today he get a blank window when he navigate to his site, and when i wanted show from where is this error is comming and wanted checked his database using phpmyadmin i remarked that it don't load his database as you look here - Removed -, also when i was going to whm and restarted the mysql service it works .. but i remorked this error 2 times now, and the client is not happy with, can you please tell me from where is this error comming, and how to fix it for good ? thanks amine