Unable to find Less Secure Apps setting

It was a temporary problem on Google's side. By 11:44 UTC it was back for us. https://twitter.com/gsuite/status/1257266044957319169?s=20

We managed to fix it quickly using App Passwords. For anyone using Less Secure Apps login, this is a trivial fix. You just need to set up 2FA (if you don't have it already) and use the generated App Password for logging in from your app, instead of the standard password.

https://support.google.com/accounts/answer/185833

This is easier than migrating to OAuth, often the only option, for anyone in a rush to fix this in production.

If you are a Gsuite admin, you need to migrate it to oAuth. I don't know if google has disabled LSA for temporary period or permanent.

https://gsuiteupdates.googleblog.com/2019/12/less-secure-apps-oauth-google-username-password-incorrect.html

LSA is back in security settings, guess it was down for sometime.