why doesn't a BOYA BY-M1 mic record sound on vids on iphone7?

i used two different adapters to connect the BOYA BY-M1 to the iphone7 : one supplied by apple with my phone and one that i purchased. the BOYA BY-M1 mic does record sound if i use it on my laptop.

the BOYA BY-M1 has two setting -- for phone and camera. i'm clear on that.

Also, when i plug-in the BOYA BY-M1, i cannot hear Siri when she speaks. then i unplug the mic, and i can hear siri.