Mail Not delivered within Domain

[Olster]

We are running Exchange 5.5 SP4 at 2 branches with a VPN between the branches and replication setup between the 2. Intermittently the same 2 users can send an e-mail with a list of names both Internal and External and some of the Internal names which are located at the other branch will not get the message and a an error will be returned to the sender saying Your Message Did Not Reach some or All of the Intended Recipients.
The addresses exist and I have checked the sender does not have these people in his local contacts with an incorrect e-mail address.
Below is the message received for all the users failed, I have removed the company details.

Staff Members Name on 28/04/2003 10:04 AM
Unable to deliver the message due to a communications failure
The MTS-ID of the original message is: c=AU;a= ;p=(My Company);l=(Senders Server)-030428000315Z-75744
MSEXCH:MSExchangeMTAReceivers Location:Receivers Server)

Any help would be appreciated.
Olster

 

[jcck2003]

first, make sure you have the needed Exchange services running, especially the MTA

also try this Microsoft KB
Microsoft Knowledge Base Article - 813748

see if these helps

 

[Olster]

jcck2003, sorry for the delay in getting back to you but I was away on a course.

All the Services are running.

KB article was looked at but the registry key value does not exist on both of the Exchange Servers. The closest thing to Dispatch remote MTA messages is Dispatcher Threads.

Any other ideas?