Mail System Error - Returned Mail

[Mail Administrator]

The original message was received at Wed, 7 Sep 2005 10:57:38 +0200 from [142.183.31.99]

----- The following addresses had permanent fatal errors -----
<databases na linux.cz>

----- Transcript of the session follows -----
... while talking to linux.cz.:
>>> MAIL FROM:"Mail Administrator" <noreply na linux.cz>
<<< 506 "Mail Administrator" <noreply na linux.cz>... Address unknown