This has been going on for many months, I can't reply all to a group email I have sent, but instead get an error message even though all my settings are correct as far as I can see, saying: Alert An error occurred while sending mail. The mail server responded: 5.7.0 Authentication Required. Learn more at 5.7.0 https://support.google.com/mail/?p=WantAuthError q11sm3428627pfh.132 - gsmtp. Please ensure that you are using the correct identity to send and that the used authentication method is correct. Verify that you are allowed to send via this SMTP server with your current credentials from your current network. Please help if can, this is very annoying, the only solution I have found is start a new email, copy the subject line and message, attachments etc and re-add the recipients and then it goes. This is true everytime in this situation re: replying to group from email I originally sent. Hope this is clear, thanks for any help.