On Tue, 29 Jan 2019 17:38:37 +0100 Vinsonnaud Ludovic <ludovic.vinsonnaud@institutoptique.fr> wrote:

Today I've got other errors (joined to this mail)

It seems to affect Dell N2048P, N4064 and Cisco 2960

  File "/usr/lib/python2.7/dist-packages/twisted/internet/epollreactor.py", line 158, in _remove
    del selectables[fd]
exceptions.KeyError: 22

I don't think this affects any specific device type. This appears to be
a bug with connection handling in the Twisted framework - and once it
occurs, it tends to bug up for the lifetime of the process. I've seen it
multiple times, but unfortunately, it seems the bug has not been closed
by upstream yet [1], even though a pull request containing a solution
was opened two years ago.

Restarting the ipdevpoll process tends to resolve it.

[1] https://github.com/twisted/twisted/pull/594