My Minecraft Resource Pack is not working properly - what to do?

I create MInecraft texture packs myself and everything else was always ok, but when I changed some textures a few days ago and adapted them to Minecraft version 1.16.1, the texture of blocks and items suddenly no longer showed ingame.

I can't explain how this happens because otherwise it always worked perfectly. I then tested the texture pack, which does not work in 1.16.1, in other, lower Minecraft versions, so it e.g. But in Minecraft version 1.14.4 it didn't work either and only the GUI and the pause menu (everything except items and blocks) in Minecraft from my texture pack were displayed. The texture pack can be tested on request.

The texture packages are very sensitive, a small mistake and the nether has default textures, maybe you used the wrong resolution / size or you haven't downloaded the 1.16 textures and instead overwritten the old textures, i.e. The same format / size / resolution but are not the same in 1.16