iPhone/iPad apps asks to allow the use of the microphone. If you have once declined the app to access the microphone, please check the following steps:
Allow the browser to access your camera and microphone when the browser asks for a permission. Choose "Allow".
If you have not allowed the browser to access your microphone, go to "Settings" and choose "Privacy"
Open the microphone settings
Check if the app has allowed the use of the microphone
IOS 11
IOS 11 asks to allow the use of microphone. If you have once declined the app to access the microphone, please follow the steps below:
Chrome
Open Settings
Check if Chrome has allowed the use of both camera and microphone
Safari
Open Settings
Check if Safari has allowed the use of both camera and microphone