Mail alias for foreign domains?

I have created an alias that is supposed to forward to both Hotmail.com and gmail.com, but either it tales hours or they dont show up at all…

I get:
Out: 451 4.3.5 Server configuration error
In: DATA
Out: 554 5.5.1 Error: no valid recipients

As an error… Are there any additional log files i could analyze?

You can try /var/log/mail.log.