The usual cause for this error (socket closed unexpectedly) is that the schedd is very busy and took too long to respond to the clientâs request (usual client timeout is 20 seconds). The SchedLog doesnât show when the clientâs request first arrived, so itâs hard to confirm this without data from the client side. This particular request was a condor_q (or htcondor job status) command.
If you see a large time gap in the SchedLog just before this error, that can indicate a singular issue tying up the schedd as the cause, instead of too much work to do.