1. Problem definition
The other person doesn't hear you. The microphone doesn't seem to be working.
1st variant: Microphone data protection settings are active
- Navigate to the Start menu> Settings (gear)
 - Find Microphone and select Microphone - Privacy Settings 

 - Now make sure that the access to the microphone for apps is activated 
 
2nd variant: The microphone volume is set too low
- Navigate to the Start menu> Settings (gear)
 - Find Microphone and select Input Device 
 - Select Input> Device Properties
 

- The volume is set low> increase it to a value that suits you (e.g. 85%).
 
