I manage an Exchange server and lately have been having an issue sending email to some recipients. The only change I have made to the configuration of the server is we changed our ISP a few months ago and other than that no changes have been made.
The issue I have is there are a few companies that are able to send emails in but when someone tries to respond they receive a message about their email being delayed. When I check the exchange systems manager I see the message in the queue and it says there was an SMTP protocol error.
There were no issues sending emails to these companies till the ISP change but that was the only change made. The mx records point to my new IP address anyone else experience this issue or no a fix for it? Any thoughts or suggestions would be greatly appreciated.
Thanks
