Out going mail has stopped working - the mesages are not leaving the exchange servers.
We have 3 exchange servers all doing the same thing all of a sudden
The message just sit in the queue with one of the following error messags:-
An SMTP protocol error occurred
The connection was dropped by the remote host
The connection was dropped due to an SMTP event sink
If we send to hotmail we get #NDR 5.5.0
Our mailserver is mail.wisemanlee.co.uk 18.104.22.168
The SMTP Diagnostics at MXtoolbox all show ok
No error's in Event log
I can connect to the server via port 25 and send myself a test email using the EHLO commands etc...
I can browse internet from all three server
Rebooted the computers
Stop and start the MTA service and the SMTP service
Please help 500 points...