Large Mail Folder and imapsync Error “NO Server Unavailable. 15”
I was having issues migration the “Sent Items” folder on a hosted Exchange 2013 account to Microsoft 365. The hosted Exchange 2013 server was returning a “NO Server Unavailable. 15” error when trying to select the “Sent Items” folder with 33,000 messages. Digging further, I couldn’t find anything until I stumbled upon this thread on … Read more