Name server change with registar and email quit working

We use SaaS with McAfee, no appliance onsite.

Basically Thursday we were getting email just like we always have.  Our website creator moved our website to Dreamhost.  They had me go to Networks solutions (where we get sradesign.com from) and change our name servers.  Dreamhost then asked for our mx records so they could add them to their server.  The changes were made and now email is just spooling with McAfee.  I know it could take 72 hours for this to start working but I've never waiting that long.  I talked to McAfee support and they said our inbound server connectivity was not working (mail.sradesign.com) and I needed to make sure it was correct on my exchange server.  It's always been mail.sradesign.com and hasn't change.  Do I need to give Dreamhost more information?  I don't do a lot of exchange support, if it works I don't mess with it.