What might suddenly provoke this poplib error?

[dn]

On 14/10/2022 01.47, Chris Green wrote:
> I have a short python3 program that collects E-Mails from a 'catchall'
> mailbox, sends the few that might be interesting to me and dumps the
> rest.
> 
> It has suddenly (after working for some years) started throwing the
> following:-
> 
>      Traceback (most recent call last):
>        File "/home/chris/.mutt/bin/getCatchall.py", line 83, in <module>
>          pop3.pass_('brzmilla')
>        File "/usr/lib/python3.10/poplib.py", line 218, in pass_
>          return self._shortcmd('PASS %s' % pswd)
>        File "/usr/lib/python3.10/poplib.py", line 181, in _shortcmd
>          return self._getresp()
>        File "/usr/lib/python3.10/poplib.py", line 157, in _getresp
>          raise error_proto(resp)
>      poplib.error_proto: b'-ERR internal server error'
> 
> 
> The section of code throwing the error is as follows:-
> 
>      #
>      #
>      # Connect to the POP3 server, get message count, exit if no messages
>      #
>      for t in range(10):         # retry 10 times
>          try:
>              pop3 = poplib.POP3_SSL('mail3.gridhost.co.uk',timeout=300)
>              break
>          except TimeoutError:
>              if t == 9:
>                  log.err("Timed out 10 times, giving up")
>                  exit(1)
>              else:
>                  log.warn("Timed out, try " + str(t))
> 
>      pop3.user('catchall at isbd.net')
>      pop3.pass_('brzmilla')
>      numMessages = len(pop3.list()[1])
>      if (numMessages == 0):
>          break
> 
> 
> It seems to be saying that the POP3 server has a problem, if so there's not
> much I can do about it as it's my hosting provider's mail server.  Is it
> really saying the server has a problem?


There's a range of possibilities here. The first question to ask (as you 
probably have) is "what has changed?" - has the Python/PSL on this 
computer been updated*, has the computer's SSL/TLS library been updated, 
etc. Then there are possible changes at 'the other end' - per previous 
responses.

* IIRC the last changes to email lib were circa 3.5, but poplib's doc 
page shows more recent updates - including to timeouts in v3.9 (YMMV).


There are changes afoot in the TLS arena. Older algorithms being dumped, 
and newer, stronger, harder, faster, better mechanisms (with racing 
stripes) being added. Not using POP3, I can't say how much impact such 
may have...

Try using an independent checker to investigate continuity of access. 
 From your own machine (I use "s_client -connect..." but for IMAP), thus 
should be able to replicate the 'error' conversation at the level of the 
POP3 'conversation'. Alternately, use an on-line service such as: 
https://www.wormly.com/test-pop3-mail-server
Disclaimer: again, not using POP3, I have never used this service, it 
'popped-up' whilst searching on DuckDuckGo.


Many general-purpose service/server-providers seem rather heavy-handed 
when it comes to email security, often as a result of some knee-jerk 
response to a 'live-issue' - ultimately caused by them not having 
competent email-specialists on-staff. Accordingly, they may have 
'changed policy' and 'forgotten' to let mere-clients know. (although, if 
your standard email access continues unabated, this seems less-likely) 
That said, it never hurts to ask/be in friendly-contact...


PS is that really your password? If so, ...
-- 
Regards,
=dn