Scheduled reports queue error "..database connected could not be opened"

Hello!

I'm coming across the error "The user has successfully authenticated, but a database connection could not be opened" with scheduled reports (the red text error in the queue). Has anyone come across this, or any ideas on which credentials to check? No issues logging into the application on our local machines, but I did notice the same error popped up when I tried logging into the application directly from our Application Gateway server.

Thanks!

Allan