All this is urgent please help. While applying patches tonight I rebooted my exchange 2007 server and now I don't seem to be able to send messages to certain outside domains.
Delivery has failed to these recipients or distribution lists:
Your message wasn't delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.
The following organization rejected your message: nlpi136.prodigy.net.
Sent by Microsoft Exchange Server 2007
Diagnostic information for administrators:
Generating server: server-v.domain.com
nlpi136.prodigy.net #550 5.7.1 Connections not accepted from servers without a valid sender domain.nlpi136 Fix reverse DNS for 126.96.36.199 ##