I have a some mail aggregation software on my Server2012/Exchange2013 box called Mailforward.
On occasion I receive the aforementioned error during the phase the application is passing emails onto the local receive connector. I cant think what has changed within my environment that has recently induced this annoyance. I don't recollect seeing it before, any idea's what is likely to be causing this? And one more thing if you don't mind i have run the command.
Oh and for extra brownie points does anyone have any idea why my Exchange management Shell command
efault Recieve Connector" -MaxInboundConnectionPerSo
Appeared to be accepted but had no effect and I still get the 421 4.4.3 error shown in the log?