dovecot - Apr 2021 - connection closes every 10 minutes

Greetings,

I use mutt on Ubuntu to access my IMAP mailboxes, on my Centos email
server that runs dovecot. Everything has worked without problems for
years. About one week ago, the connection between mutt and dovecot
became unstable.

Before, I could leave mutt connected for days in a row, no problem.
Now, everything still works fine, except... I get every ten minutes I
get "connection timed out" in Mutt's status line, and hundreds of
messages like

Apr 12 16:12:49 SERVERNAME dovecot: imap(ACCOUNTNAME): Logged out in=164 out=757

what puzzles me is that I did not touch anything both on my server and
on my desktop, except an "apt-get update" some days before this
started.

But cannot see how it would be related anyway, nor have I found
anything online like this.

Any help to understand what happened and fix it is very welcome.

Marco

> On 12 Apr 2021, at 16:47, Marco Fioretti <marco.fioretti at
gmail.com> wrote:
> 
> Apr 12 16:12:49 SERVERNAME dovecot: imap(ACCOUNTNAME): Logged out in=164
out=757
This log line means that the connection with the server is terminated
gracefully, with the client issuing a "LOGOUT" command. That makes me
think the issue is on your mutt client's end and not with dovecot.

Best regards,
Eirik

update on this:

to make a long story short....

1) I did run mutt with debug enabled , but could not recognize anything useful

2) I had the same problem with mutt from my laptop

3) a few days ago I received a new modem from my ISP, as part of their
network upgrade operations

4) more or less in the same moment the problem I reported here
disappeared. Now mutt stays connected even 24 hours without losing
connection.

I am NOT 100% sure that the problem disappeared AFTER the change of
modem. That happened during a few chaotic days, both work- and
family-wise, so I did not take notes. And modems may have nothing to
do at all with the disconnections. But now the problem is not there
anymore, I have no clue what may have happened, and if anybody can
guess... thanks in advance.

Il giorno lun 12 apr 2021 alle ore 16:47 Marco Fioretti
<marco.fioretti at gmail.com> ha scritto:
>
> Greetings,
>
> I use mutt on Ubuntu to access my IMAP mailboxes, on my Centos email
> server that runs dovecot. Everything has worked without problems for
> years. About one week ago, the connection between mutt and dovecot
> became unstable.
>
> Before, I could leave mutt connected for days in a row, no problem.
> Now, everything still works fine, except... I get every ten minutes I
> get "connection timed out" in Mutt's status line, and
hundreds of
> messages like
>
> Apr 12 16:12:49 SERVERNAME dovecot: imap(ACCOUNTNAME): Logged out in=164
out=757
>
> what puzzles me is that I did not touch anything both on my server and
> on my desktop, except an "apt-get update" some days before this
> started.
>
> But cannot see how it would be related anyway, nor have I found
> anything online like this.
>
> Any help to understand what happened and fix it is very welcome.
>
> Marco