PE won't load on Amazon Fire HD 6.

Both of my sons have a 2015 Fire HD 6 (4th Generation) and are playing version 1.6.1.0 of P.E., and neither can get past the "Minecraft" white screen for the past 2-3 weeks. 

 

I cleared the cache, uninstalled/reinstalled the app, and searched the Internet for a solution, but have not found any fix. There seems to be a lot of other players having the same issue in forums, but no one has posted a fix. 

 

Can someone please help me fix this?

 

Thank you!