With some of my Bluetooth devices, speaker and headphones, I have a problem. When I connect the paired device it disconnects again after a few seconds. I have to disable and enable Bluetooth or sometimes reboot the phone to get the device to connect and stay connected. If it was only one device I would assume it was something wrong with that device, but since it's two different devices, one speaker and a set of headphones, I think it may be something else wrong. I use a Moto G5+ running Android 7.