External Microphone is not working on Video Recording

Im Using TNVI Wireless Mic. To connect it to my phone im using lightning to TRS adapter which work fine when i try to use on voice memos. The problem comes when i try to record it using Video Recorder. It doesnt detect my external mic instead using built in phone mic. How come it can work well with voice memo and not with video recording. I had find the same problem and no solution for everyone. Do Help me. I use Android before it works like a charm with this external mic.

Note : You can see how i connect the receiver on my iphone on the image here