[Bedrock] skin will not upload despite following classifications

I created a skin with the skindex/Minecraftskins.com and it will not upload. It says skin must be 64x64/64x32/128x128 and a .png. I have verified that it is both a png and 64x64 yet it will not upload still. Any idea as to why? I'm on an Amazon fire tablet if that may mean anything