Since I updated to Mac OS X Sierra, my Thunderbird client keeps asking for my Mac email password and fails to logon. I then receive a message saying that the Mac mail server has disconnected. My Mac password hasn't been changed recently and other email accounts, gmail & hotmail are working fine. This issue is happening on both my MacBook Pro's, I know I am entering the correct password as I logon to iCloud without any trouble, the email account settings in Thunderbird appear to be correct, the server settings are the same as if I try to set up a new Mac mail account in Thunderbird.