Problem sending email to a 1and1 hosted domain

[timbo343]

We have an issue with a 1and1 domain that we usually send to. Suddenly we are getting an error:

554.mail.com (mxgmxus004) Nemesis ESMTP Service not available 451-4.4.0 554-No SMTP service 451-4.4.0 554-Bad DNS PTR Resource record 451 4.4.0 554 For explanation visit http://postmaster.gmx.com/

 

This is happening on our Exchange 2010 box. We used to have to use our ISP to relay messages to this domain - this is now no the case. The send connector that we used to relay emails won't send to this problematic domain.

 

I was wondering if anyone has seen this or knows how to solve it.

 

We can send to all other domains without any issue, even AOL.com -we used to have a major problem sending to them.

[timbo343]

Nevermind - i restarted the transport service and the exchange server managed to send the emails.