Upgraded to 12.2 and through web clients I was getting a Database connection failed. Checked the error log and it was complaining about not being able to find
fileNotFound C:\Program Files\QlikView\Server\QvConnect64.EXE) occurred during open of C:\Program Files\QlikView\Server\QvConnect64.EXE
Well, I think the installer possibly didn’t place it correctly? Anyways, to fix it just copy
C:\Program Files\QlikView\QvConnect64.EXE into the Server folder C:\Program Files\QlikView\Server\ and then the magic works again