Less Secure Apps Your Google Account. This is most likely to impact users of legacy email, calendar, and contacts apps. Make your account more secure.
When you add it back, make sure to select google as the account type to automatically use oauth. Now click the back arrow in the title, you can find the allow less secure apps has been turned on. Now turn on allow less secure apps:on toggle button in the new page.
Start with a security checkup.
I literally have to click the advanced options and proceed anyway in order to sign in. This is the solution to this issue, especially if you still received a “this setting is managed by your domain administrator.” even if you do manage to get to the “enable less secure apps” page. In thunderbird, gmail imap mail accounts can connect using oauth2 instead of ssl/tls. Google/gmail calls apps that don't support oauth2 less secure.
