Help with the OBJ models

Hello, I use the Mcreator 2020.2 for the Minecraft 1.12.2, two of my OBJ models was black, i have look in the logs and one of the texture was not load, i have try on the 2021.1 with the plugins for the 1.12.2 and i still the same problem, how i can solve that ?

He says me :

OBJModel: A color has already been defined for material 'ModelMaterial' in 'testnew:models/item/bae_caiman_test.mtl'. The color defined by key 'Ks' will not be applied!
OBJLoader.MaterialLibrary: key 'Ns' (model: 'testnew:models/item/bae_caiman_test.mtl') is not currently supported, skipping