Yes you can Dana

Awhile back there was a rash of spam emails coming from RR accounts and (always) AOL accounts. Therefore a lot of places implemented a broad banning of those addresses.

Since then about half of the sites have lifted the ban, some have done a partial/temp lift, and still others kept it in place.

This also happens with ip addys and can be the reason some folks have problems or get the you've been banned message.