If you made a custom JSOM model and imported in MCreator, but in Minecraft, you see black and purple texture instead, this page can help you resolve this problem.
To resolve this issue, open your JSON model file you imported in MCreator with a text editor or inside MCreator using integrated code editor. Then check the following:
The model parent model needs to be vanilla
Look for a line that looks like this
This line's sometext must start with minecraft: to override the Minecraft model as a parent. In most cases, this line is not needed at all and can be omitted.
Example of a ticket from our issue tracker: https://mcreator.net/tracker/issue/50321
You used non-standard rotation angles
Minecraft JSON models can only have a standard set of rotation angles. These are 0, 90, 180, or 270 for block models and 45 through -45 degrees in 22.5 degree increments for item models. More info: https://minecraft.gamepedia.com/Model
Your model contains invalid characters
Model parts and groups can only contain standard English alphabet characters, numbers and underscores. All other characters can cause the models to not work properly.