I have set up a Connector in Exchange 2010 under Server configuration Hub Transport called Relay. This allows users specified on an ip address list to send email through exchange.
Reason being, a few users have 2 email addresses, the Exchnage address and a pop email address for another domain. Email is delivered fromt he pop address to the exhange inbox and I want the user to be able to send a new email from either address. No problem with the @exchange address, all working fine, but the @popaddress needs permission to relay through exchange.
All of a sudden one user can no longer relay. I've checked the machines ip is on the list but I just get Server error: '550 5.7.1 Unable to relay'.
I sent an email from another machine on the ip list and it realyed no problem.
If I send an email to an internal email it sends, it just won't relay to an external address. Telneted to the exchange server and sent an email from command line and got the same message.