[snip] > Result: 25: SMTP error from remote mail server after RCPT TO:<
> test123@???>: 454 4.7.1 <test123@???>: Relay
> access denied
The sender (exim) does not have a problem, it seems working correctly,
tries to forward the mail. The receiver (postfix) refuses to accept the
mail. If it really IS responsible to accept mail to help.uber.com, there
must be some misconfiguration in postfix, or some other reason for
denial (sender not allowed, spam, virus, but not reporting this properly
- which is also a misconfiguration, but MIGHT be wanted)
Is it really true, THIS is the only sender having problems?
> Do you think Uber's DNS configuration for help.uber.com is problematic? Is
> this the expected behavior for Exim? Or is it possible that this Exim
> instance has some kind of configuration that could cause this?
The DNS configuration might not be optimal, as some already said, but at
this state (we already talk the right MX) not relevant to exim.
Do you have access to the postfix logs and configuration. (But then you
should turn to get help from some postfix user list.)
