Question

facebook error session expired

Answer 1

If all fail, why not u try reseting the game?
Last time when there was a major issue , gumi ask to do the following

1. Start the game
2. When the splash screen appears, press and hold somewhere on the top part between Wiki and Support
3. Eventually u get a pop up message to sleet data

This means that it reset the whole game them u need to login Facebook again on the game and re-download all the game data again

Good luck. Do at your own risk !!

Answer 2

Go to settings > Facebook and then uncheck and recheck the brave frontier button. Restart brave frontier and it shouldn't give you the error anymore. Worked for me. Hope it helps!