I configured Mutt using IMAP connecting to my TU Dresden ZIH mail account.

Here you see the working result:

set check_new=yes
set copy=yes
set folder="imaps://mail.zih.tu-dresden.de/"
set imap_check_subscribed=yes
set imap_keepalive=120
set imap_pass="my_secure_pw"
set imap_user="s1234567"
set mail_check=600
set timeout=600
set spoolfile="imaps://mail.zih.tu-dresden.de/INBOX"
set folder="imaps://mail.zih.tu-dresden.de/"
set mbox="+INBOX"
set postponed="+saved-messages"
set record="+sent-mail"


Setting mail_check, imap_keepalive and timeout was some kind of trial and error because I have got a tls error after beeing idle for some time. With the actual values everything works fine for me.