Ensure sidekiq is running?

First upgrade to the latest version (there are some new patches related to this I think that went in a few hours ago). Open yourwebsite/admin/upgrade and upgrade to the latest version (+101 is working for me now, so you’re good there)

Then from the terminal

cd /var/discourse
sudo ./launcher enter app
rails c
Sidekiq.redis { |r| puts r.flushall }
exit
exit
sudo ./launcher restart app

Then reboot the machine. I did this loop 2 times and it solved the issue.

I think someone also mentioned you can try a few things

  1. Leave it for 24 hours and the scheduler should kick off again and this error should go away
  2. Force the schedules to start, open yourwebsite/sidekiq, goto scheduler and trigger the schedule Jobs::VersionCheck