CMK version: 2.0.0p21
OS version: Ubuntu 20.04
You can see the notifications trying to be send in mail.log - but they are send using the wrong mail address ion scheme of sitename@localhostname. The the smtp and mailutils is therefore sending an error message that sitname@localhost is not allowed to send any mails by using the configures mail address. When I’m trying to send any mails using the OMD [sitename] manually like echo “” mail -s a.s.o. there is no problem and mails are beeing delivered correctly.
Have you got any ideas how to change this strange behavior.