I was having this issue for so long. Where I would attach my microphone with a audio adapter, and it won't work.
Please note that you need to have a headphone jack adapter which is supported for your smartphone, and you are correctly joining the wire of microphone with your adapter.
If you are struggling with the same, do the following steps:
1. Go to developer options. You can enable the developer options by going into About Phone, then going into software information, and then click build number 7 times.
2. Click on the disable the USB audio routing option. This will disable the automatic routing to USB audio peripherals.
There you go! Now, your microphone will start working with your smartphone!
