Instagram / Facebook in app browser won't allow access to the microphone in my web app

Question

I have a web app ( built in React ) that needs the user's microphone so they can speak to their device. When people sign up, I ask for permission to their microphone. This all works great in all the major browsers.

The problem is in the Facebook / Instagram in app browser on Android phones - in that browser, the user clicks the "Grant Microphone Access" button, and nothing happens. Does anyone know why this is?

I'm hoping to either find out how to allow the microphone within the Facebook / Instagram in app browser ( on Android phones ), or find a way to force the link to my web app to open in Chrome or Safari.

Thanks for your help.