2 domains, one mail server- sender rejected, domain not found

I currently host two domains on my network. I am not able to send mail from one of them. My primary domain, bluespringsgov.com, works fine. When trying to send from my second domain, bluespringsedc.com, the messages bounce back with "Sender Address regected. Domain not found." I have a barracuda spam firewall, which is the sending mail server for both domains. I can receive for both domains, without a problem. It looks to me like the recipients mail servers might be doing a reverse lookup on the sending ip, which is 216.60.82.33. The PTR record resolves to barracuda.bluespringsgov.com. Could this be the problem since the sending server is resolving bluespringsgov, yet the recipient mail server is expecting bluespringsedc? Any help is very much appreciated. I do have a copy of my zone file if needed.