The app is blocked when I try and login to uPar with Google:
The message you are seeing is from the Google admin console and your Google Admin would have to confirm permissions for the third-party app settings in the Google admin console. ( This is part of the New Third party app settings Google pushed out for all third-party apps.)
Your Google admin would need to do the following:
Login to the Google Admin console.
Navigate to Security>APIControls>App Access Control
Under Apps Pending review or Configured apps search for: Don Johnston Inc
Click on the line that displays Don Johnston inc.
Click on Change access.
Select your Google OU(s)
Click on Next.
Follow Google's prompts to set the permission level.