Managed to fix it.1) Update the facebook mobile app.2) Open the facebook mobile app and log in.3) Go to Menu -> Settings & Privacy -> Settings -> Media -> Links open externally4) Try opening the Gear Vr app again (Worked this time)

I have exactly the same issue. I get "For your account security, logging in to Facebook from an embedded browser is disabled"I have linked my Facebook and Oculus profiles.