doom emacs mu4e msmtp

[yallebud]

What would you like to know?

Dear Henrik,

I desperately try to make mu4e, in particular msmtp, work. I have succeeded in reading my mails with mu4e, but I have tried in vain up to now to send mails via msmtp. I can send mails from a terminal without any problems, but emacs tells me constantly relay access denied. As I cannot see any entries in the log file of msmtp, I think that emacs never calls msmtp to send mails. I have followed the instructions in https://docs.doomemacs.org/latest/modules/email/mu4e/? My OS is an up-to-date ArchLinux. My emacs version is 29.1, my doom version 3.0.0.-pre. Can you please help me?
Thank you very much.
Best greetings
Joachim Köstler