I've an issue with my QMC, the tasks are shown as "Unrunnable" and "Cluster is down". But in the Services tab, the service is running. And when I check the tasks detail/log, I can see that the tasks are running normally, just that I cannot monitor the status and start/stop the job.
Thanks Maria. I followed steps no. 4 (recreate the distribution service folder) and it worked. But not all jobs are runnable after recreating the folder, so I have to manually disabled/re-enable those jobs to make it runnable again.