cheerio2065

so I was trying to upload my world right. It was crashing due to to many items being droped at once so i had to put the world intop single player and use commands to kill any floating items. the world runes in single player fine now but when I try to /ul world it just says "invalid files". why are they invalid? they work in single player! anyone have an answer? I was following the official minehut upload guide if that helps at all. https://www.youtube.com/watch?v=AeJ71A3-6pg