Jenkins works during days and then no jobs can be run anymore on any slave

I have a Jenkins 2.235.1 and it works great. but sometimes (at least 3 times), I don’t know why but no job can be run anymore.

the job don’t even appear in the “slave queue” whereas the same job worked great the day before.

Where can I find clue to debug this ? I checked quickly in the log file of Jenkins but I don’t find anything.

the only solution is to restart Jenkins but it will block in a few days again.