Go to your Google workspace admin console (admin.google.com) logging in with your work account.
In the menu, go to: security, access and data control, API controls.
Select "manage third-party app access"
Select "configure new app"
Enter this code to search:
31542749347-gh00oi4n5h625sbg7ms3e00uqi8c9mt7.apps.googleusercontent.com
Select all orgs
Select "Trusted"
Save the settings
Once complete, move on with step 2 in the ProLine integrations page