[Cant invite to party]

Its happening to me as well, practically unplayable.  I just opened a ticket with WF.  I am join some groups but very few.  Most of the time I get, "Failed to join Session"  I was talking to a guy and he said it showed me offline, even though I was chatting with him.  When he tried to invite or vice versa we would get "Spooley appears to be offline" but after relogging, I would get the "Failed to join Session".  The game is unplayable if we can't make premades.  I remember hearing about DE migrating servers or updating the network, sounds like they have some major issues to deal with.  

 

Note: I can join mission via the star chart fine from what I can tell, this is just with invites etc.