Morning All,
I have a strange issue that's cropped up all of a sudden on an Exchange 2010 box. There are a bunch of Contacts for the entire organisation in a public folder - lots of individual contacts and lots of contact lists, all external people. This Contacts folder
is available to everyone with certain people having edit, delete permissions. All working as intended.
Except for one group. For some reason - any attempt to email this group sits in the Exchange Queue with an: - 421 4.4.2 Connection dropped due to connection reset error after every single address in the list and never sends, eventually an NDR will go to
the sender with the above error.
All other addresses and distribution groups (configured exactly the same way) work 100% fine. It's just this group! I asked the people who created this group to re-create it from scratch, which they did - with the exact same error!
We also use a 3rd Party mail provider to receive/clean all mail before it enters and leaves our system. They are set as our 'Smart Host' in Exchange. We are having zero issues with them or any error reports from them.
All the email addresses look fine, and I can email each person individually fine. I have re-created the send connector as per a quick Google on this error - with no success at all.
Any ideas are appreciated because I have no idea what to try next ;)