No sound from Minecraft but Discord already (headphones)?

I recently bought new headphones, the Razer Kitty BT Kraken Edition. I was able to connect to my laptop with no problem, but when I tried to play with a friend I noticed that I could only hear her voice through Discord, but not the noises from the game.

If I'm only in Mc (without having a conversation in Discord) then everything goes perfectly.

Can someone help me there?

There's a setting in Windows to use other audio devices for communication. In addition, you can partly set in the programs which audio device you use, Discord asks if you want to use the new device when you plug it in.

Open your audio settings and try to select your headphones