You may be able to resolve this issue by taking the following action:
1. Sign in to your Tableau Online account via browser.
2. Navigate to your Account Settings page (click on your user icon at the top right)
3. In the Connected Clients section, delete any connected clients for the Bridge machine, and then attempt to re-launch Bridge.
For more info, see the "Remove a user’s connected clients" section in: Access Sites Directly from Connected Clients