We recommend that only System Administrators should be able to process oAuth for the V4S Mobile app. By default, all Salesforce users have access to the V4S Mobile oAuth from their Salesforce ID. The default permission to access V4S objects is through the ID of the System Administrator who installed the V4S Mobile app from the AppExchange. If a different Salesforce user clicks the V4S Mobile oAuth link, it could cause problems in your login process for all V4S Kiosk and V4S Personal users.
As the non-Salesforce administrators do not have access to all the V4S Mobile objects or some Standard objects in Salesforce. The V4S Kiosk and Personal User will see an error message as "invalid grant: expired token" when they try to log in. And the Volunteers see the same error message when they try to Signup or Check-In/Out for a Job or Shift on the device screen. We suggest that only Systems Administrators must have access to the oAuth link. Systems Administrators can enable or disable oAuth option to other Salesforce users.
Here is what you need to do to hide the oAuth authentication link,
Now only the Salesforce profiles you selected in the profiles screen will have access to oAuth for V4S Mobile app when they log in to their Salesforce Account.
Note: Once you have followed the above steps and saved the changes, please process oAuth again from Salesforce Administrator ID and then start using the V4S Kiosk or V4S Personal application. Otherwise, the V4S Kiosk or V4S Mobile Users see an error message as "Invalid_grant: expired access/refresh token" when they try to log in to the V4S Kiosk or V4S Personal app.