I always blame DNS when a domain moves. In my mom’s case, it took 5 days for everything to catch up. In the mean time, you can just use the IP address.
Weird about that new email address. I suggest you use webmail.yourdomain.com to send the message and see what it does. Seeing how webmail is internal to DreamHost, it should have better luck. If that doesn’t work, delete the address, wait an hour (it may take less than this, but just to be sure…), then re-add it.