"User is authenticated but not connected" when trying to use ThunderBird as mail client access office365 after confirmed below:
1. Ensure that the user name and password are correct and that the same user name and password run properly on the OUTLOOK client
2. The message can already be Sent and received by the peer end, but the sending will stop forever at 100% copying the message to the Sent folder, and the sent message is synced in Sent mail box in Outlook client.
current configuration for Server :