If you receive an error in the microphone section in test.mashme.io please check the following:
Step 1: Check your system settings
Make sure your microphone is on the default recording device, and that recording levels are correct:
-Mac
If the device you want to use is correctly configured, go to Step 2 and Step 3
Step 2: Check that you have closed all other programs that may be using your microphone. These could include:
-Skype or Skype for Business
-Another browser tab or window
-Audio recording software
Step 3: If you’re using a headset, make sure the mute switch on the cord is off. Also, make sure you aren't muted on the website
If after completing these steps the test results are not satisfactory, there might be a problem with the permissions in Chrome/Firefox
Step 4: Check the browser permissions
Using Google Chrome:
-Open Chrome.
-Go to test.mashme.io and mashme.io site
-When prompted, choose Allow
-To change a microphone permissions
-Open Chrome .
-At the top right, click More 
Settings.
-At the bottom, click Advanced.
-Under "Privacy and security," click Content settings.
-Click Camera or Microphone.
-Turn Ask before accessing on
More information available in Chrome KB
Google Chrome uses your camera & microphone
Using Mozilla Firefox:
-Click on the site identity icon (the lock symbol)
in the address bar.
-Select Allow on each menu next to Use the Microphone:
-Click anywhere on the web page to close the menu,
then click the Retry button.
Note: If you are running MAC OSX 10.14.x Mojave or later, please check "Security and Privacy" settings, then under the "Privacy" tab, please check that the microphone is permitted in the Browser.
Step 5 If after all these steps, the microphone is not working, please
contact your hardware manufacturer and/or use a different
input device