I had an issue on using HID to control the media in Android. It worked fine at the first connection, I could play , pause and change the song on phone. But it couldn't control the media again after reconnection . The example of HID could work fine after reconnection. I added the example code of HID to my project without any change. Is there any way I can find the problem. My project uses nrf51822 with sdk9.0.0 .