I can't talk to friends in Fortnite, what can I do? What was wrong?

In Fortnite I can hear other players, but they can't hear me. What can I do against it? Did I do something wrong in the Fortnite settings?

Check if you have voice chat in the settings and push to talk off. If so, go to Options = Voice Channel and select the voice channel in which your teammates are. Or maybe you just muted your headset. Have fun.

Thank you very much, I'll give it a try.