Addon Failed To Load

Hello,

I'm so sorry if this is the wrong place to ask. When I was done making my theme, I tested it, it worked. But whenever I upload it outside of "about:debugging#/runtime/this-firefox", it says it appears to be damaged. I checked my manifest file, then tried zipping it with WinRAR, and then via powershell, yet it still doesn't work. Does anyone know why this happens, and more importantly, how to fix it?