My client is hosting their own email rather than it being hosted and controlled in the DNN hosted plan. I think this is causing issues with successfully sending out newsletters.  I am able to send "test" proof emails to a role group I've specifically set up for this purpose. No other emails are going out, however and I received this error on a test to myself:

Error in processing. The server response was: 
Could not load DRD for domain (louisville.com) 
rcpt (dat at louisville dot com)

What is causing this and how do I fix it in a hurry?

Thanks - Dan Vonderheide

I don't have access to their email server...this is something set up on their end? Or is this something I configure in >host settings?

I THINK I was able to get this hammered out.  However, I'm not convinced that all of my emails were sent.  I did receive several "delivery failure" bouncebacks, which was due to mis-typed addresses, so that told me that some emails went out.  I did not receive a bulk email confirmation, which I usually do.  Other Admin-level subscribers have mentioned that they didn't receive it either.

What could possibly be going wrong at this point and how can I confirm the number of mails sent?