Forcing Facebook's App To Open Links In Your Default Browser Instead Of The In-app Browser
1 – Launch the Facebook app and log into your account.
2 – Tap the Menu icon (it looks like three horizontal lines).
3 – Scroll down and tap Settings & Privacy.
4 – Tap Settings.
5 – Scroll down and tap Media and Contacts.
6 – Toggle the “Links open externally” setting to On (it should turn from gray to blue).