Can't connect to a specific friend

When I try to connect to a friend's xbox party, it says that I can't join the party. This happens sometimes. However, I can never join this specific friend's game.

We play Assassin's Creed 4 Multiplayer together frequently but it doesn't let me connect to his game session, and he can't connect to mine as well. It was fine a couple of days ago. I've already portforward my xbox a long time ago too. I can connect to
all of my other friends except this specific friend of mine.

Any suggestions? I'll link my friend to this post so he can discuss as well.

:)

 

Can't add a specific friend...

I'm trying to add Trepidwinter256 to my friends and I keep getting the same error message :

Sorry, we could only save some of your changes. try saving again.

I can add other people and remove them as well. It seems the problem is specific to that gamertag.

Thanks.

 

Can't add a specific friend

I used to have this person on my friends list for years then, one day it removes him off my friends list. I tried to add him again and it gives me the message off xbox can't do this at this time. When in a party I can't hear him and he can't here me, yet
everyone else can hear both of us. We tried several things and can figure out a way to add each other. We both Don't know what to do?

 

Yea we are having this problem in conneccting also like he said the game session is no longer available.