Try these steps
1. Check that the camera or mic control is on in Here. They are separate controls. 2. Open Here's device settings and select the camera or microphone you want. 3. Open your browser's site permissions, often beside the address bar, and allow camera and microphone access for Here. 4. Check your computer or phone's privacy settings too; the browser needs permission to use the devices. 5. Close other apps or tabs using the device, then refresh Here.
Still no microphone sound?
Check a headset's mute switch and make sure the selected microphone responds. Try without Bluetooth to rule out a headset connection problem.
Still stuck?
Try an updated browser. Inside a room, use Report video problem to tell us what happened. See reporting a video problem.