Returned mail: Data format error

The original message was received at Fri, 8 Jul 2005 00:16:56 -0400 from lists.plug.phoenix.az.us [32.240.112.136]

----- The following addresses had permanent fatal errors -----
lurker@lists.plug.phoenix.az.us

----- Transcript of session follows -----
... while talking to server lists.plug.phoenix.az.us.:
550 5.1.2 <lurker@lists.plug.phoenix.az.us>... Host unknown (Name server: host not found)