I setup this account last month and everything was working fine.  Now I cannot send and receive....I am getting bounce backs like the following.............

Delivery to the following recipient failed permanently:

      jcoment@poolsharksoftware.com

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain  poolsharksoftware.com  by mail.poolsharksoftware.com .  [208.88.78.213 ].

The error that the other server returned was:
550 < jcoment@poolsharksoftware.com > No such user here