Our CEO is getting this message when trying to send an email to an individual who uses Road Runner. I followed the tenet instructions on another post here and I got an error when I did "rcpt to: email@example.com". I got "550 #5.1.0 arress rejected." I tried a valid email address as well and got the same error. When I look at the outbound queue in Exchange Manager I see a blue check mark for that domain as well as one for Sprintpcs.com. I have an SPF record in place, reverse dns works, althougth the name of the Exchange Server shows up as Barracuda(which I installed about a month ago) with it's associated IP address instead of the name and IP of our Exchange Server. Any direction would be greatly appreciated. It's difficult explaining anything to our CEO.