Why will my mic work for phone calls but not on any applications?

1. Make sure the mic is not set to mute.
2. Check your battery charge. Low charge may turn off video.
3. Your operating system appears to be Marshmallow. I am not sure what application you are attempting to use for voice chat. It might be Google Duo, Facebook Messenger, Hangouts, or Imo, among others. If an application is not working, one generally tries reinstalling it.
4. Another application may be running and blocking use of the mic. Check what else is running. I think holding down the home button will reveal what is running. Shut down background apps and test the app you are using. Google Play may have What's App to check this.

Okay well, there can be a few possibilities :
1) Your microphone is muted. May be you mute it accidentally while you are on phone. Or maybe you've made some changes to your hardware recently but installing some app- all in all just make sure the microphone isn't muted.
2) Your phone microphone is damaged. In that case you need to get it repaired from a nearby mobile center. If you still have your phone under warranty then you can get it replaced by the company itself.

One way to check whether your mic is broken or not is try using earphones with a mic. See if the other person is able to hear or not.

Do try to reboot your phone. That sometimes fixes the problem.
If that doesn't seem to work,
Long press the menu button to access "google now" page. Hitting menu again gives settings option. From there, disable voice open for OK google.

Good luck!

You might try going into settings > applications and clear out the Phone App cache and possibly the data.

First u have to check that ur microphone is working correctly or not for this use hands free. If hands free works perfectly then then ur microphone speaker is damage u have to change it.

Hello,the problem you are could be caused by so many thing,but i will love to know if the phone does ring out if you are called,and also when yo receive calls do you hear them,if the phone does not ring,i advice you buy a new ringer because the one you have in there is definitely damaged,and if you don't hear people when they call,that means you also have problem with your ear piece which you can replace by getting a new one at a mobile phone store.
The phone could also face a jammed application problem or a virus attack,which means if it is flashsed you might have it working as supposed.

wish you good luck,

take care.

SInce your voice is not heard to the calling person there is a issue in the Mic.Conatct service centre and check Mic whether it is working fine and no prolem in it .Before that there is any test for mic (refer manual) peerform it and ensure it was the problem

be sure that the applications are compatible with ur phone...
if so the application would be corrupted and needed to be downloaded again

Switch off cellphone and press and hold CALL + 3 + * and press power button dont unpress these CALL + 3 + * keys for 1 minute.After that your phone will hard format. Now your problem will be solved.Thanks

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ok attila, your problem is your mic,, here's what they are going to do..(the pro's ) open your fone and in the lower section where the mic and the contact point located. they are going to test it if the mike is still ok, if it is ok, they're going to clean it with solutions u'r mic and contact point, and it will going to work out fine, but if not they have to replace u'r mic...