I have tried solve this for many many hours ;(
macOS 11.1, Emacs 27.1 (brew), Gnus 5.13, msmtp 1.8.14 (brew)
I use GNUS to read maildir that is synced using mbsync. I can read mail using GNUS but sending gives me
Warning: Opening nnimap server on office365...failed: ; Unable to open server nnimap+office365 due to: office365/imaps nodename nor servname provided, or not known
Sending via mail...
Opening nnimap server on office365...
Server nnimap+office365 previously determined to be down; not retrying
Opening nnimap server on office365...failed:
gnus-inews-do-gcc: Can\u2019t open server archive
The mail is sent but GNUS think it is not. I can send email from the command line without any error or warning, so this should not be a msmtp configuration problem
cat msmtp-test.txt | msmtp -a default [email protected]
The msmtp exe pointed out by the sendmail-program is verified to be used. I tried just about everything, the simple
(setq sendmail-program "/usr/local/bin/msmtp")
(setq send-mail-function 'message-send-mail-with-sendmail)
(setq smtpmail-debug-info t smtpmail-debug-verb t)
and many other settings I found on various pages.
Any hints what is going on or how to debug this is appreciated,