Recording with my phone's built-in mic while using headphones

Hello dear n-Track community,

I want to do some multi tracks vocal recordings in n-Track on my phone (Google Pixel 6a with GrapheneOS) using the built-in microphone and regular headphones (no mic) through a USB C to jack 3.5 adapter. It is not working, nothing is being recorded. In the basic recorder app of my phone, it works by itself but not in n-Track. I tried a bit to fiddle with the audio configuration in n-Track with no success.

What shall I do?

Thank you.

Ok, the real problem was that n-Track wanted to test the latency and wanted me to unplug my headphones adapter for that. What I did was keep my adapter and connect it to a speaker instead of my headphones so I could perform the test. Now it seems to work fine.