Can't connect to any aspect of MP,

The game is asesticslly astounding, I just got the Halo 5 bundle yesterday and made all the downloads and updates the same day. When the game was ready for play I quickly hopped into the campaigning without even looking anywhere else. After a bit I decided I’d check out MP, it didn’t matter if it was on war zone, arena or custom games I could not find a “suitable server” that would allow me to connect and play anything . is this a connection issue on my part because I have friends that are playing the game just fine. Also just to add this in; people can’t hear me when I plug in my default headset and no its not muted.