I have a regular problem where I queue up to play story and 10 to 15 minutes go by and I am not matched up with anyone. Eventually I give up and play solo. It happens so regularly to the point where I am only playing with others 10% of the time. I can only find others on occasion. This is on Xbox one.
What region/time zone are you in? Did you try posting in the XB1 On-line play forum? There’s at least one running thread for people looking for partners - might be easier to group up and then use the private match option. Matchmaking for story does seem to be variable on the XB1 this weekend - sometimes players are found really quickly and other times not. Plus, 2 or 3 times I’ve been waiting for that last player, they join and then instantly back to an empty squad because someone gave up just after the squad was completed - argh!
I’m in US central time.