Vinod on Bulk data upload from electron - example code gives error 500, 1 or 0.

Have you considered modifying this example and seeing if this works from your device: 

https://www.mathworks.com/help/thingspeak/bulk-update-a-thingspeak-channel-using-particle-photon-board.html

I believe that your POST does not contain the right fields you will get a 400 or 401 response code.