The first thing I can think of is that the emulator wasn't allocated enough resources (RAM, CPU, etc), or the Mac you're using doesn't have enough. Another is that idk if the version of Nox you had has openGL3 or higher, but that probably wouldn't have allowed you to even install FT from Play Store, or open the app.
The last thing might be a compatibility issue between Nox (on Mac) and FT itself. I know that Nox (and most emulators) have features that many devs block, reaulting in the apps not working right on the emulators. RuneScape mobile is one such app that isn't emulator compatible, for example.
All in all, it's not really possible to know for sure without logs from the emulator, and/or crash reports. I wish you the best of luck in trying to get the game running, though.