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tdb2022
Copper Contributor
Jun 02, 2022

500 5.3.3 Unrecognized command

Hi all,   Our exchange 2016 server start acting up in the last couple days without any configuration changes. I see a few "500 5.3.3 Unrecognized command" in ProtocolLog\SmtpSend. 500 5.3.3 Unreco...
2016
Exchange Server
tdb2022's avatar
tdb2022
Copper Contributor
Jun 07, 2022
I found the problem. It's the GFI MaillEssentials greylist. Don't any error after disable Greylist in Anti-Spam filters.