Cannot connect to Halo 5 Guardians lobby service

Just like the topic says. I’ve hard reset my system, reset both my modem and router, and still cannot connect to multiplayer lobby service. Xbox Live is functional. I can play other online games (ESO, Destiny) and stream Netflix. Couldn’t find any recent posts about this. All the ones I’ve seen are for the UK but I am in the US.

I’m having the exact same issue, except I’m over in the UK :confused: