Delivery to the following recipients has been delayed

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:". 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 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.
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tamaneriConnect With a Mentor Commented:
If it's saying the address is rejected, it sounds like perhaps the recipient's domain has blocked yours... potentially inadvertantly. I'd check with the recipient to ensure they didn't add your domain to their spam list.
InSearchOfAuthor Commented:
Well, I went to their link for requesting removal of blocked status but apparently we are not listed in any of their blacklists. They provide links to check your IP address and it comes up OK.
InSearchOfAuthor Commented:
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