[X-Newbies] Email delivery problem with ntlworld

[Keith MILLS]

Hello

This is not really a Mac problem, but I do not know where to turn and 
any advice would be gratefully received.

Over the last the last three months or so, I have not been able to 
reach customers and friends who have ntlworld email addresses (but with 
no other providers). I send the message - and after about five days it 
is bounced back to me with the could not be delivered message. I keep 
getting the following:

> Action: failed
> Status: 4.0.0
> Diagnostic-Code: X-SMTP-Server; host 
> smtpin.ntlworld.com[81.103.221.10] said:
>     452 Message rejected (in reply to end of DATA command)

I know the  receiving mailboxes are active - I can get messages from 
them. Two different friends tell me that I am the only person having 
this problem.

I have twice contacted the postmaster at Wanadoo and have so far 
received no reply. I thought that I would contact ntlorld directly, but 
their website gives no information on how to do so!

Sorry if this is outside the scope of the list. But we are losing 
friends and business! So, if anyone can  point me in the right 
direction, I should be very grateful.

With thanks
Keith Mills