请查看线程:https://groups.google.com/forum/#!searchin/firebase-talk/liu/firebase-talk/ms_NVQem_Cw/8g7BFk1IAAAJ它解释了为什么会发生这种情况.这是因为 Google 电子邮件被验证存在一些安全问题，而 Facebook 电子邮件则没有.

Please check the thread: https://groups.google.com/forum/#!searchin/firebase-talk/liu/firebase-talk/ms_NVQem_Cw/8g7BFk1IAAAJ It explains why this happens. This is due to some security issue with Google emails being verified whereas Facebook emails are not.