One Friend i cannot join or invite to a Squad

[(PSN)Wisky]

I used to be able to join him a week ago but now when i try to join him it say please wait after 5 mins of waiting for it to load it closes the friends list and does not join. It also doesn't even give me a error that i couldn't join so i tried again, same thing happened. I then sent him a invite and it said he joined but on his screen it said please wait but he was still in a Solo Session he was also frozen and had to quit his game. I have even tried forcing a match and it showed his ship but he did not load in, his name was in the squad but he was not there. this is a brand new bug for me and never had this problem with him before on any game other than Warframe.