“I can hear other people but they cannot hear me … my microphone isn’t working.”
Here’s the fix:

Press the Windows key or search icon on your taskbar and type “Microphone privacy settings”:
Windows Microphone Privacy Settings Bridge Phone System Voip

Click microphone privacy settings and scroll down until you see Allow desktop apps to access your microphone:
Kotter Group Bridge Voip Phone System Windows Microphone Desktop Access Settings

Make sure from that “Allow desktop apps to access your microphone” is enabled as shown.