Sophia Mail uses Microsoft365, but it has been announced that Microsoft365 will eliminate basic authentication to improve security from October 1, 2022.
As a result, if you are using e-mail software that uses basic authentication after October 1, you will no longer be able to send and receive e-mail, so you will need to take separate action.
Instead, advanced authentication (OAuth authentication) will be introduced. OAuth authentication is already enabled on Sophia Mail, so if you need to change your settings, please do so by October 1.
Please refer to the link below for more details.