Joining Public games

Anyone else having issues joining public matches?

I like to play the game on my own but there’s an achievement for playing with 2 other people so was just trying to join a lobby to get that but I always get connection failed

There’s an issue with match-making, especially on PS4 right now (and to a lesser extent XB1). There are some work-arounds listed in the threads you can try if that’s your platform. I suggest you follow-up in the relevant thread. (There are also the On-line Play and Trading sections - it may be easier to join through a party than random open matches.)