IMAP && Server certificate has expired

[John Levine]

In article <20200531180822.GA10779 at c720-r342378> you write:
>El día domingo, mayo 31, 2020 a las 06:11:44p. m. +0100, Ottavio Caruso via freebsd-questions escribió:
>
>> On Sun, 31 May 2020 at 17:10, Matthias Apitz <guru at unixarea.de> wrote:
>> >
>> >
>> >
>> >
>> > Hello,
>> >
>> > When I connect with the MUA mutt directly with IMAP to my ISP with:
>> >
>> > $ mutt -f imap://imap.1blu.de:143/
>> >
>> 
>> Have you tried port 993?

Try it yourself, same response.  The cert on this server uses a Comodo intermediate
certificate issued 20 years ago that expired yesterday.

>but I don't know if I've to fix this locally or the ISP.

It's the ISP's certificate, only they can get a new one.

The sensible thing for them to do is to get a free cert from Let's
Encrypt and set up your scripts to renew it automatically as needed,
generally ever 90 days. That's what I do on my mail servers.