You’ll need to add more details. Output of journalctl -u dynflow-sidekiq@orchestrator and contents of /var/log/foreman/production.log would be useful.
Sorry for dregging up this old thread, but I ran into the same issue. In my case, the logs for journalctl -u dynflow-sidekiq@orchestrator were insignificant, but /var/log/foreman/production.log showed the following message:
After checking that there were no other orchestrator processes running, I cleared Redis using redis-cli flushall. Which immediately allowed the orchestrator to start up again and pick up where it left off.