I'm getting this Unknown Error when calling UpdateUserData from a Unity build on Android. I'm able to make several successful calls before this happens (I'm calling it roughly once a minute). I never encounter this error in the Unity editor, only ever on Android (not tested on iOS), so it can't be a problem with the request. When I call it again the next time it works. So it's just failing for no apparent reason maybe 1 in 10 attempts.
HttpCode: 400
HttpStatus: BadRequest
Edit: Should probably also point out that this is on wifi and connected to the same network that I'm connected to in the editor with no problems.