Not Connected To Xbox Live (Yes I am)

Howdy Folks.
So every time I try to play online in MCC, I get this message.
“You are not connected to Xbox Live and will not be able to access this feature”
I am connected to Xbox Live, though. I can get on Halo 5 no problem. I can get on the Internet no problem. Just can’t get on MCC.
Am I doing something wrong? I’ve tried hard resetting my console. I’ve taken the disk out, then back in. I’ve checked my online and network connection. It’s all fine.
If you have any words of advice, it would be greatly appreciated.

I have this very annoying bug too… I have to restart my console.

It’s a glitch many people have, unplug your xbox (while its off) and wait 30 seconds before plugging it back in. Turn it on and it should work.

I just keep backing out and back in, and after a couple times it finally let’s me in

Playing this game today, July 23 2017, and what do you know? Nearly three years later and this problem hasn’t been fixed. Of course, it’s an easy fix for us, but I’d prefer if it didn’t do it at all.

Yeah, me too. There is no reason this shouldn’t be fixed.
Really amazing actually.