Fix no sound on iPhone after iOS11 upgrade

Problem:

After updating my iPhone to iOS11 I am facing a sound related problem. Until the upgrade, the call function was working all fine. After the update during any call, the speaker function automatically disabled, even the volume buttons are not working. Sometimes the person on other side was unable to hear my voice. 

How to fix no sound problem on iPhone after iOS11 upgrade

Set the mute switch on

This is one of the basic things but sometimes user ignores it. Check and ensure that the mute switch is set in ring mode.

Noise cancellation feature

Go to settings > General > Accessibility > Phone noise cancellation and tun it off. After that reboot your device. This should fix the no sound issue.

Turn WLAN off

In Telephone option in settings, you can find WLAN button. Make it off and restart the device.

Receiving off

Disable 'Airplay' option and do a hard restart. Now press airdrop icon and select 'Receiving off'. Again perform a hard restart. This solved the iOs11 issue for many users.

If you tried all the above solutions but failed to solve the issue then try a hard reset by holding down the power button and the home button. Let the phone shut down and then turn the phone back on. See if that solves it.