Exchange Migration: "421 4.4.2 Connection dropped due to SocketError."
During an Exchange migration, the "old" Exchange server may not be able to deliver mails to the new Exchange server. This happened during an Exchange 2013 to Exchange 2019 migration. Mails on the Exchange 2013 server to mailboxes that had already been migrated to Exchange 2019 could not be delivered. The ... Read more
