Here are some potential solutions if your microphone isn’t working in Microsoft Classroom:

1. Check the microphone settings – Go to the microphone control panel and ensure the microphone permissions allow for Microsoft apps to access it.
2. Check your hardware – Make sure the microphone is securely connected to the computer, and that headphones are not plugged in (which can block the microphone).
3. Test the microphone – Go to the app's settings and test if the microphone is working.
4. Restart the computer – Often this is enough to resolve any microphone related issues.