When connecting the Bluetooth on our Units, your 

Smartphone will ask for a password pin to connect

Check if the Pin is correct 

The Default Pin is 0000


If you did put the correct password - Maybe the settings on the Unit is not Correct

try the next steps below \


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we can also check the settings to see if it is on the correct

Bluetooth Module


should be Wenqian BC6

or WQBC6 


something along those lines


Check 

Settings

System Vers/info (7890)

System Settings


Scroll down to Bluetooth Module