POP3轮询和SMTP发送均突然失败

[JammyDodger]

您现在可能需要在您的 Google 帐号中启用两步验证 (2FA)，并设置一个应用专用密码：

Connection to the POP3 server is failing with an authentication error. Please check your POP3 settings

I recommend turning on 2FA on the account and setting up an App Password for Discourse. The policy change is about the “allow less secure app access” option being deprecated. More info on this here: