I had to delete one of my Gmail accounts from my desktop Mac. Now I am unable to reinstall it, and get a pop up message saying: You can't sign in to this app because it doesn't comply with Google's OAuth 2.0 policy for keeping apps secure.
iMac (2017 – 2020)
+1 on a brody's assessment. What version of macOS are you running?
You can't sign in to this app because it doesn't comply with Google's OAuth 2.0 policy for keeping apps secure.
We are seeing a lot of people with older versions of mail reporting that error, and that Google not longer supports old Apple Mail versions. They have to use a browser to check their GMail.
If you post the SUB-MODEL of your iMac from "About this Mac..." we can see if you have an OS upgrade path available. Example:
For security reasons, please DO NOT post the serial number.
+1 on a brody's assessment. What version of macOS are you running?
You can't sign in to this app because it doesn't comply with Google's OAuth 2.0 policy for keeping apps secure.
We are seeing a lot of people with older versions of mail reporting that error, and that Google not longer supports old Apple Mail versions. They have to use a browser to check their GMail.
If you post the SUB-MODEL of your iMac from "About this Mac..." we can see if you have an OS upgrade path available. Example:
For security reasons, please DO NOT post the serial number.
Older Mac OS preset Gmail Account settings may be outdated. Visit http://www.gmail.com/ and edit your preferences to allow for IMAP checking of your email, and add Other... type email with Mac OS Mail with the IMAP settings Google recommends.
Can't add Gmail account to my iMac account settings
