Bluetooth pairing fails, no more PIN entry field I wanted to pair a bluetooth device (specifically, Dynamo Harvester) with my Moto G 2 (Android 6) with the normal workflow: Open bluetooth system settings, scan for devices, select Dynamo Harvester, enter the PIN and it is paired.

Now, after entering the wrong PIN (0000 instead of 000000) several times – where most of the time a message was displayed that the PIN was wrong –, I entered the correct PIN, and something strange happened. The Incorrect PIN message popped up for a brief moment, and afair the device moved to the list of paired devices.

Since the app still did not recognize the Dynamo Harvester, I turned bluetooth off and on again. Now the device has disappeared from the list of paired devices, but appears in the scan list. If I try to pair, I cannot enter a PIN anymore but receive a message Can't communicate with Dynamo Harvester. 

I thought that perhaps the device is broken somehow, but connecting with a Samsung Android tablet worked just fine (with the correct PIN). 

What can I do? Might this even be a bug in Android because of the strange message about the incorrect PIN, although it was correct?
I recently had a similar problem though different devices (Android Google Nexus 7 running Marshmallow and Motorola Buds Bluetooth headset). Turns out the headset needed a reset to forget all the devices it had learned. Since I switch between devices, I suspect my data in the headset itself had become corrupted. In any case this fixed my problem. You might try finding a headset reset for your device and see if that fixes your problem. You may also need to have your phone/tablet forget all the devices, too, as that has helped me in the past.