Time Needed : 10 minutes

As long as this isn’t an issue with the hardware, you should be able to fix it by doing one or a couple of procedures. That said, here’s what you should do:

1. Force restart your phone

   When it comes to fixing issues you’re not familiar with, it’s better to perform the forced restart before anything else because it is possible that the problem is caused by a minor glitch in the system. 
   
   1. To do this, press and hold the volume down button and the power key for 10 seconds. This will force your phone to power itself down and turn back on. 
   2. When the logo shows, release both keys and wait until the device has finished rebooting. 
   
   If this doesn’t fix the problem, move on to the next solution.
   

2. Test the loudspeakers

   After doing the forced restart and Google Duo still has no sound during video conferences, what you have to do next is test the loudspeakers of your device. 
   
   You can do so by turning the volume all the way up and then playing a video or a music track. If your phone plays the audio without any problem, then it means the speakers are working properly. 
   
   If not, then it is possible that there’s a more serious issue with the firmware. So you have to do a couple more things. 
   

3. Clear the cache and data of Google Duo

   At this point, it’s possible that the problem is caused by an issue with the app. What you have to do next is to reset Google Duo itself and that means clearing its cache and data. Here’s how: 
   
   1. Go to the screen where the Duo icon is located. 
   2. Tap and hold on the Duo icon until options show. 
   3. Tap App info. 
   4. Touch Storage. 
   5. Tap Clear cache. 
   6. Now, tap Clear data and touch OK to confirm. 
   
   Most of the time, this will fix any app-related problem and this might be what you need to make Duo work perfectly again. However, if the problem persists, then move on to the next solution. 
   

4. Reset the settings

   After the first three procedures and your phone still has no sound during video conferences using Google Duo, then the next thing you need to do is to reset all settings. This will bring all your phone’s settings back to factory defaults. It’s possible that some settings are causing this problem and since we don’t know which setting it is, it’s best to just reset all settings. Here’s how: 
   
   1. Swipe down from the top of the screen to pull the notification panel down. 
   2. Tap the Settings icon on the upper-right corner. 
   3. Scroll to and tap General management. 
   4. Touch Reset. 
   5. Tap Reset settings. 
   6. Tap the Reset settings button. 
   7. If prompted, enter your PIN, Password or Pattern. 
   8. Finally, tap Reset.
   
   As long as this is not an issue with the hardware, these procedures should be able to fix the problem.