application server suddenly cant read tables in database server

Hello,

We are using Yii 1.x framework and we are using Microsoft SQL server 2012 for database

we have 2 servers; one for application, and one for database both running on windows environment

suddenly the application server can’t read the tables on the database server it give something like “The table dbo.users for active record class cant be found in the database” and we have to restart the database server once again, knowing that in term of memory and space we have 32GB RAM, more than 400GB hardesk space.

I am not sure what is causing this, even though the CPU and RAM performance are pretty normal.

Anybody can help me with this?

Regards,

Amena Shweiki