With some hosts, I get this error when trying to send emails so far the only hosts I have received this error from are citaq.com and phomemo.com things like gmail.com or another mailcow instance i manage work fine and i can send emails
here is the full error the system emailed me:
This is the mail system at host mail.mydomain.com.
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# THIS IS A WARNING ONLY. YOU DO NOT NEED TO RESEND YOUR MESSAGE. #
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Your message could not be delivered for more than 4 hour(s).
It will be retried until it is 5 day(s) old.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<info@citaq.com>: Host or domain name not found. Name service error for
name=citaq.com type=MX: Host not found, try again
and here is what i get in the postfix log:
NNLLLLNLNL: to=<info@citaq.com>, relay=none, delay=10678, delays=10670/0.06/8/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=citaq.com type=MX: Host not found, try again)