Updates past 3.6.0-2-01 will not start - web server error

[brad-taylor-yvr]

Running system on version 3.6.0-2-01.

Upgrading to any version newer than that, causes the same error to appear.

2023-01-02 15:39:51,963::INFO::[notifier:123] Sending notification: Error - [02/Jan/2023:15:39:51] ENGINE Error in 'start' listener <bound method Server.start of <cherrypy._cpserver.Server object at 0x7f7b86a33400>>
Traceback (most recent call last):
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cheroot/ssl/builtin.py", line 99, in _loopback_for_cert
    thread.start()
  File "/usr/lib/python3.10/threading.py", line 935, in start
    _start_new_thread(self._bootstrap, ())
RuntimeError: can't start new thread

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cherrypy/process/wspbus.py", line 230, in publish
    output.append(listener(*args, **kwargs))
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cherrypy/_cpserver.py", line 179, in start
    self.httpserver, self.bind_addr = self.httpserver_from_self()
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cherrypy/_cpserver.py", line 170, in httpserver_from_self
    httpserver = _cpwsgi_server.CPWSGIServer(self)
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cherrypy/_cpwsgi_server.py", line 99, in __init__
    self.ssl_adapter = adapter_class(
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cheroot/ssl/builtin.py", line 225, in __init__
    _parse_cert(certificate, private_key, self.certificate_chain),
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cheroot/ssl/builtin.py", line 121, in _parse_cert
    return _loopback_for_cert(certificate, private_key, certificate_chain)
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cheroot/ssl/builtin.py", line 107, in _loopback_for_cert
    thread.join()
  File "/usr/lib/python3.10/threading.py", line 1091, in join
    raise RuntimeError("cannot join thread before it is started")
RuntimeError: cannot join thread before it is started
 (type=error, job_cat=None)
2023-01-02 15:39:51,963::ERROR::[_cplogging:213] [02/Jan/2023:15:39:51] ENGINE Error in 'start' listener <bound method Server.start of <cherrypy._cpserver.Server object at 0x7f7b86a33400>>
Traceback (most recent call last):
  File "/usr/lib/sabnzbd/venv/lib/python3.10/site-packages/cheroot/ssl/builtin.py", line 99, in _loopback_for_cert
    thread.start()
  File "/usr/lib/python3.10/threading.py", line 935, in start
    _start_new_thread(self._bootstrap, ())
RuntimeError: can't start new thread

This looked similar to the weak SSL cert failure described here:
Q3: https://github.com/binhex/documentation/blob/master/docker/faq/sabnzbdvpn.md

I have removed the self-signed cert files and they were regenerated, but the error persists and the web server does not start.

I also tried switching the enable_https property from 1 to 0 in sabnzbd.ini, but this setting does not stick - it always resets back to 1.

Rolling back to version 3.6.0-2-01 restores the application. It looks like whatever change was made before Sep 12 (tag 3.6.1-1-02) is the origin of this problem.

let me know if you need more info... thanks.