Can't hear audio in VoIP call when i grant media permission to webView

VoIP call works perfectly fine at start until i grant access to WKWebView media(microphone access). I am using WKWebView to highlight the spoken word using web speech engine.

If i use webView i can't hear VoIP call audio and if i stop webView VoIP call works perfectly fine. What i want to achieve is to stay in VoIP call as well as work with webView to highlight the spoken words and I want to know if there is any problem in giving microphone access to VoIP as well as WKWebView simultaneously.

Please post your question if i am not clear about anything or you want to know more information.