My friend and I got Dying Light on release day and have been playing multiplayer everyday since then. There were no problems. Then one day when we logged on we could no longer do multiplayer. When we go into our games, they say our game visibility is "Single Player", even though under options we have Friends Only for online. Changing the online setting to public does nothing. Restarting the PS4 does nothing. Does anyone know what to do?
So apparently in addition to the prologue, the ending must be played by yourself. My friend and I just happened to quit right before starting the last mission. I guess the game has logic to block your multiplayer if you're on the last main mission, even if you have side quests. Once we finished the main quest we were able to do multiplayer again.
The main problem with the crashing until they fix it is that: the games restrictions on how "your" game and your partners games need to match the server is to tight. When you play note that the game will almost always crash during a change in the environment. An air drop, an event, and when the weather changes from sunny to rainy. Me and my friend tested this for a few hours last night and it seems to be pretty consistent. If one or both of you are lagging and the server does a check to see if you are both in the same game state and your not, it will always crash. They will fix it.