Hello Bujdosó Levente,
Welcome to Microsoft Community and we regret the inconvenience caused to you.
Your JBL microphone is may not be recognized or configured correctly by Windows. Please try to select System > Sound > In Windows Settings and check if your JBL microphone is listed and selected as the default input device. If not, you can try clicking "Manage Sound Devices" to add or enable your JBL microphone.
There is a conflict between your JBL microphone and Windows privacy. Try selecting Privacy > Microphone in Windows Settings and check whether apps are allowed to access your microphone and whether the app you want to use is allowed to access your microphone.
Your JBL microphone may have an issue with a Windows driver or update. Please try to update your driver and Windows. In Windows Device Manage > right-click on it and select "Update Driver" or "Uninstall Device." So that your Windows will re-recognize and install your JBL Microphone.
If you have another one(microphone)then also try to see if you can use the speaker. Of course I wanna know if your JLB can be reproduced this issue on another machine.
Thanks for your patience!
Best Regards,
Lenka-MSFT| Microsoft Community Support Specialist