Why do I not get into a match?

Since yesterday I've been trying desperately to get into a match. After I press PLAY, the loading screen comes up. Then I'm back in the lobby. Is it a Fortnite issue or is it my PC?

It may be because your Wi-Fi no longer makes it possible for you to "communicate" with other players (i.e. You can't join the round). With Fritzbox you can change that in the settings of the router. But I don't know all that well about that.