I typed up a real nice question which i just lost thanks to my apple magic mouse scrolling feature. So here is the short and sweet version.
Cant send email to only two domains. Message stops in Exchange queue with this error: 421 4.4.0 Remote server response was not RFC conformant
Google searches have taken me down the DNS path so I took a look via MXToolBox.com. Everything seemed to check out. Also ran Exchange mail flow tools, looks good. I do receive a nice little bounce back with #550 4.4.7 QUEUE.Expired; message expired ## which is just telling me the message timed out in the queue. The recipients say they have not had complaints from anyone else, just me.
Thanks in advance for any help you can provide. This has been an on going issue and I am about to wrap some blue cat 5 around my neck and jump.