Undeliverable Mail

[monksey]

I am receiving an undeliverable message from the System Administrator when I send or reply to mail from a particular domain. The message I receive is :-

Your message did not reach some or all of the intended recipients.

Subject: FW: Order
Sent: 06/01/2004 12:29

The following recipient(s) could not be reached:

'recipient@domain.com' on 06/01/2004 12:29
The recipient name is not recognized

The recipients email address is valid because i am able to send to it from a hotmail account.
I am running Exchange 5.5 SP4 on a Windows NT 4 platform.
Please help, this is driving me nuts. All other domains can be sent to, it's just this one I'm having problems with.

 

[search66]

Are *you* the Exchange admin? Do you have a firewall? Chances are someone or something internal is blocking the email.

 

[monksey]

Yes I am the Exchange Admin. We do have a firewall which is managed for us in Maidstone by our mother company. We do not have any problem receiving mail from the domain but just cannot reply back.