issues with external mic with my iPhone 11 Pro

I have an external mic called PowerDeWise which I had used successfully with my iPhone 11 Pro to record videos in my backyard. But last time I was doing a video outside the screen the mic seemed to be working for a while but then there was a message on my phone screen that said "ringer" and then the screen just turned blank. When I disconnected the devise and tried to listen what I had recorded, the video visual was there but no sound.

Any Suggestions?? anybody??? Please