Since the upgrade tasks are not running. Even when clicking the start button, nothing is happening.
This is a major issue.
I think you need to provide more details what has upgraded QV and/or OS, to which releases. Are there changes on the server user-accounts, run the services, worked the access point and some more.
Upgrade QlikS ense Enterprise 2.1.0 to 2.2.3
Sorry, by Sense Enterprise I couldn't help.
Adding RootAdmin to user sa_scheduler "Admin Roles" and restarting de server.
Coincidence or Solution ... do not know!
Retrieving data ...