

If you do not take one of the following actions, when LSA access is discontinued after February 15, 2021, you will begin receiving an error message that your username-password combination is incorrect. User instructions If you are using an app that accesses your Google account with only a username and password, take one of the following actions to switch to a more secure method and continue to access your email, calendar, or contacts. February 15, 2021- Access to LSAs will be turned off for all G Suite accounts. Users who have connected to LSAs prior to this date will be able to continue using them until usage of all LSAs is turned off. This includes third-party apps that allow password-only access to Google calendars, contacts, and email via protocols such as CalDAV, CardDAV and IMAP. Access to LSAs will be turned off in two stages: June 15, 2020- Users who try to connect to an LSA for the first time will no longer be able to do so. Moving forward, only apps that support a more modern and secure access method called OAuthwill be able to access your G Suite account. Access through only a username and password makes your account more vulnerable to hijacking attempts.
AUTHY GMAIL OUTLOOK FOR MAC VERIFICATION
As part of this effort, and in consideration of the current threat landscape, we’ll be turning off access to less secure apps (LSA) - non-Google apps that can access your Google account with only a username and password, without requiring any additional verification steps. Dear Administrator, We’re constantly working to improve the security of your organization’s Google accounts. Password-based access will no longer be supported.

Starting February 15, 2021, G Suite accounts will only allow access to apps using OAuth. Then, there's this I got as a Google domain admin:
