Hi, I'm using his script with a mikrotik hotspot, after several tests I've encountered a problem with IOS devices that receive an error when logging in with Google:
403. That's an error
Error: disallowed user agent
The problem does not occur with Facebook.
I think this issue is related to Google Policies. I have no idea about your app so I can't give any solution now. You should try to read Google docs to find a way to deal with it.