Email delivery issue to Exchange 2007 server

Hi Guys,

I have one client which I have issue is delivering emails to them. They are using Exchange 2007 single server multirole and I'm on Hybrid 2013/EO using IronPort. I found and detected there server is in open relay.

Does this config in anyway affect email delivery to them?

I can always telnet to them successfully. 

NDR:

Remote Server returned '< #4.4.0 smtp; 4.4.0 - Other network problem '[Errno 0] Error' (delivery attempts: 0)>'<o:p></o:p>

BR,
Uddan