Fortnite is not working anymore?

Whenever I jump out of the battle penalty, the game crashes after a few seconds and this message comes:

The game even tells you what the mistake seems to be. Obviously, the connection is blocked by a firewall.

Do you use a VPN service or a special anti-virus program?

That's off

No

What kind of operating system do you play on? And which anti-virus program do you use?

Windows 10 and garkeins

Have you ever tried to reinstall Fortnite?

When you play Fortnite for the first time, there's a message from the firewall that you have to accept. You probably rejected that then. Just reinstall the game.