JS Jobs is down for maintenance. Please check back again soon. This message came up on my site and I had the Admin > JS Jobs > Admin > Configurations > Site Setting > Offline: set to NO

The problem was that I had nothing in my shifts area under admin/control panel.

Thanks to the Joomshark support that got back to me really quickly in the ticket system

Nat

You have to activate JS JOBS

(Oops solved) Sorry