Dear all, Microsoft banned all basic authentication method from Office365 because these method does not support multi factor authentication. After that, I reconfigured the the configuration by used OAuth2 method on latest version of Thunderbird (78.5.1 (32-bit). The result as follows: + Can not receive new email from Offfice365 (Alert: As attached file No. 1) + However, I can send the email normally with OAuth2 via SMTP Please help me fix this problem. Thank you so much for your support.