Error with mod from Minecraft Addons Maker

Hello! Yesterday I started working on my mod in the Minecraft Addons Maker program. Yesterday I installed it and played with it, and today when I finished it, it doesn't work. And the mod itself is there, I activate it, but it doesn't show up in the world. Experimental functions are enabled. My mod adds new items. I also used to develop a mod for money, when I entered the world with this mod, it also doesn't work. I also have my own mod for textures, it works. I think this is related to the new version 1.21.21. I've already tried everything, please help