I keep getting "Unable to activate skin" message

I created a new skin, and I wanted to activate it, so I went to the launcher to the "Skin" tab, and clicked "Add"

 

, and I downloaded my own skin that I created, the skin being a PNG file so I am correct, and I clicked "Save and Use", and it said "Unable to Save". I then go to another tab and back to the "Skins" tab, and the skin I wanted to save was there, but the "Current" player model didn't have my skin. Next, I hovered on my skin to click "Use", and it says "Unable to Activate". I reopened the Minecraft launcher and I don't know why it does this. Please fix this so I can use my skin.