Sometimes Jenkins goes into a state where it is unable to create new jobs through any available mechanism.

The Web UI: Main Page - New Item - Freestyle project - OK – the UI just freezes forever, with the browser showing the "waiting for host..." status.

The CLI "create-job" command – the CLI process freezes forever, returning no status and no logging.

I've tried giving Anonymous the create job permission, but that didn't help. So this is not authorization-related.

Jenkins has enough memory and HDD space.

The only temporary fix I found is to restart Jenkins. After restart, jobs are created successfully. However, after some time (a couple of days) it becomes "stuck" again: jobs are running, UI is responsive, everything runs smoothly, but jobs cannot be created.

I started seeing this on Jenkins 1.580.1, the previous LTS worked fine.

I understand that I cannot provide a reproducer, so please tell me how I can debug this issue on my side. Currently I don't see any logs when I try to create a job during the "hang".