Due to recent G Suite/Gmail changes, we recommend you make a simple change outlined below to your G Suite configuration to address this issue. Without following the whitelisting procedure below, you and your co-workers see an "Unverified App" warning when authorizing Email Sync.
Please forward the following instructions to your G Suite Super Administrator (or your IT team if you don’t know exactly who your administrator is).
- From the Google Admin Console Home page, go to Security and then API Permissions.
- Ensure that GMail API access is enabled. Disabling “All Access” or “High Risk Access” will disable Email Sync
- At the bottom of the list of apps, click the Trusted Apps link.
- Click Whitelist an App Add
- The Add App To Trusted List window opens. In the Select App Type list, select the "Web applications" option"
- Fill in the OAuth2 Client ID: 1833497015-bmp14o5q7fk0chm2gfb3bi3ruvd6s463.apps.googleusercontent.com