Screen Recording with Audio in Messenger Video Calls

I'm using an Iphone 11 with iOS 14.2, and I'd like to record my Facebook Messenger calls with the Screen Recorder. When I'm recording another app, both screen and audio are recorded very well. However, when I call someone on Messenger, audio stops recording and both audio and my mic are muted for the rest of my recording. How can I capture audio and mic on my Messenger calls? My mic is already enabled for the recording and the silent mode is turned off before starting the recording.