Android Supported Devices...only 839? Please Help:-)

So I recently uploaded an app to android and I clicked on the app once it was approved and it says my device is not supported (I tested it on my device before uploading it, so I know it can work on my device) so I figured out how to see on Google play how many devices are supported and it is only 839 devices out of 12,000?

Is there any way to make the app support more or all devices? I could see it if my phone was old or out of date by its a new Samsung phone.