[cobalt-users] mail problem

["andy" <andy@xxxxxxxxxxxx>]

Hi All
message i know get when i send a message to my server .ie
andy@xxxxxxxxxxxxxxxxxx  not andy@xxxxxxxxxxxxxxxxxxxxxx  the latter works
ok but i get this error with the first
 ----- The following addresses had permanent fatal errors -----
<sales@xxxxxxxxxxxxxxxxxx>

   ----- Transcript of session follows -----
554 MX list for webfxdomains.co.uk. points back to dns.webfxdomains.co.uk
554 <sales@xxxxxxxxxxxxxxxxxx>... Local configuration error

How can i fix this ?? I am very stuck any help would be great.
            Thanks andy