Apart from the attached, is there any other application running in the server.
Also are the services related to the application running. You can check this in services.msc
What do the logs say? Is there any error in the Windows Event Viewer? Do the accounts run with the same username and password? Did the password change recently?
Have you engaged with your IT for the basic troubleshoot?
This error is server side issues buzz when ever server will be down on that time QMC will shooing Red Banner only. Please contact with admin team.
Various OEM's have their specific troubleshooting SW.
Like iLO for HP, iDRAC for Dell, try once troubleshooting with these, you'll be able find some answers there.
As you say the server is restarting once a week, it could possibly be a HW issue (not 100%).