They enjoy breaking things in general http://googleonlinesecurity.blogspot.ca/2014/04/new-security-measures-will-affect-older.html http://googleonlinesecurity.

They enjoy breaking things in general http://googleonlinesecurity.blogspot.ca/2014/04/new-security-measures-will-affect-older.html http://googleonlinesecurity.blogspot.ca/2014/04/new-security... https://support.mozilla.org/en-US/kb/thunderbird-and-gmail https://support.mozilla.org/en-US/kb/thunderbird-and-gmail Gmail accounts created on or about June 2014 (exact date unknown, Google only mentions "second half of 2014" in their new authentication blog post) won't work with Thunderbird until the Thunderbird team implements Google's non-email-standard authentication. This is currently scheduled for Thunderbird 38 which will be released on April 7, 2015. See bug 849540 for the full technical details