No texture displayed on a model

Hi everyone,

I’m a beginner on Unity and I encountered a problem.
I have imported a 3D fbx model (Assets > Import new asset…) and when I try to apply a new material (not even an embed material) on it in Unity, only the main color on the texture is applied.
I mean, if it is a sand texture, my object will appear all brown.

I tried to change some of the properties of the model through the “Model/Rig/Animation/Materials” tabs but nothing worked for me so far.

If I apply this texture on a cylinder built in Unity for example, it works great.

Thank you !

Someone else asked the same question recently:

Indeed, I didn’t find it, thanks.

Well, I can’t use the Standard Asset shader because I need a custom shader so I have downloaded ProBuilder.
It works well.

But is there any solution to automatically create and unwrap UVs for imported models in Unity (without Blender or anything)?

Thank you.