Cant play campaign with a friend

Tried to jump on all the halos with a friend who lives down the hall from me. Needless to say i couldnt connect to him and it kept sending me the message “failed to connect”. I dont see how a game thats been out for so long and had no problems playing with friends when the game first came out so why am i having this issue this late after release?! Please fix this asap. Bungie had it right and 343 had to step in and destroy these games from my childhood.

Do you guys both have open NATs and the correct ports forwarded? You can look up guides on how to do both. Reddit has some good ones.