Go to this site. --> https://webcammictest.com/check-mic.html When you start the test, you should see a pop-up like my screenshot. What site are you trying to use that requires the mic?

Otter.ai

Tried the webcammictest and got this message:

Requested device not found No device found matching the requirements or browser can't access it.

What OS? Assuming Windows... If windows, what do you see here? see screenshot Also if windows, post a screenshot of your device manager. Here are windows instructions to get to device manager. https://www.google.com/search?client=firefox-b-1-d&q=windows+command+for+device+manager