Database Connection

I made same changes to the administration of database and also restored gateway backup to one of my old backups.
Now my gateway seems to not liking to connect to database.

Cannot create PoolableConnectionFactory (Login failed for user 'sa'. ClientConnectionId:9ff73e6a-aeb2-468d-88c0-ee01ffd9fc96)

Possible Checks done -

Any ideas ?


After I restart the server everything works fine but then a while after I get this error -