Sent folder does not sync with imap accounts on Em client

I am trying to switch to eM Client from Thunderbird. For some reason on some imap mail accounts the Sent folder does not sync from Thunderbird to eM during the initial installation. I have several imap accounts, and a few have properly synced, but not all. On the problem accounts it appears as if new messages being sent from eM are appearing in that eM sent folder however. I need to have all of the past Sent message history as well in order to switch to eM permanently.