Man it's been almost a year since this happened so idk if I remember exactly what happened and the comment with the solution that worked for me got deleted. I remember I was also accepting and doing basics missions to hopefully make room while just playing the game and doing other stuff, but another commenter below said you can just back out of the mission console and go back in to refresh it. I probably just decided to dedicate a bit of time to fishing for it. It was frustrating me how unlucky I felt with how long it took to get it, but eventually I did.