Headphones don't work on Android

I have a pair of headphones (A) that suddenly decided to stop working yesterday. When I plug them into my Oppo Reno2 Z, it continues to use the speakers. I have tried other headphones (B) on my phone, and they work just fine, and the other headphones (A) work when I plug them in to my PC.

I have Bluetooth turned off, my OS is up to date, with the last update being in August. I also used compressed air to try to clean the jack, thinking it was just dirt at first.

I really don't understand why my headphones refuse to work with only this device.