@willemdh
The most common reason for not being able to clone an ML job is that we cannot find a matching kibana index pattern.
Can you create an index pattern for heartbeat-* manually, i mentioned the method in another issue. Missing index pattern heartbeat-*
After that you should be able to clone it. Btw why you want to clone it? if job is stopped, you can delete it and recreate it from uptime UI again.