connection to dovecot times out about every ten minutes

[Marco Fioretti]

Greetings,

after years when everything worked without a hitch, mutt started to
say "connection timed out" every ten minutes or so when connected to
my remote dovecot imap server. I would need help to figure out where
the problem is, on the client or server side, and then how to fix it.
Details already are in the dovecot mailing list here
https://dovecot.org/pipermail/dovecot/2021-April/121897.html

Thanks in advance for any help,

Marco