I’m currently getting a mailer daemon error for feedback-2.2 at checkmk.com:
Generierender Server: googlemail.com
feedback-2.2@checkmk.com
Remote Server returned '554 5.0.0 < #5.0.0 smtp; The email account that you tried to reach does not exist. Please try double-checking the recipient's email address for typos or unnecessary spaces. Learn more at https://support.google.com/mail/answer/6596>'
same happens for the feedback-2.2-beta from Our plan for 2.2. Release