I have an issue with my GL300C controller. It was working fine last  week.  I go to fly and the controller won't start.   I charged it up and  had 4 lights blinking. When I disconnect the charger the lights go off  and it will not turn on. I am able to start it with the charger attached  and connect to the P4.   When I disconnect the charger the controller  shuts off / no lights.

I've posted two videos showing the problem.
             Video link
https://youtu.be/mRxCXpwiReI

             Video link
https://youtu.be/_0oqNR1NRIo
Any suggestions on how to revive the controller?                

Hi. I am sorry for the trouble this has caused. With regards to this concern. How many hours was the remote left charging? If you have left the remote controller charging for 2 hours and the issue still persists. I would recommend for you to contact our DJI Support Team to further diagnose the said remote controller. Rest assured that our DJI support team will do their best to assists your with regards to this matter. Please note that the repair cost will depend on the said warranty period of the remote controller otherwise, valid charges will apply. Thank you.

Good luck

Here is the results from my testing. See attached pics.
The battery is measuring 8.22 v and 8.31 v.
When connected to the controller nothing works.
I attached a 9v battery attached to the controller and it lit the controller with 2 white lights,
but I got a red low battery beep.
Any ideas on why the battery doesn't work in the controller when it has the voltage?
Is there something like firmware in the battery that could cause the issue?
Thanks,