Mesh does not get drawn after switching to core profile


I’m using glLoadGen to load my opengl functions, so I think I couldn’t even call functions that aren’t supported.
I’ve already set up glDebugMessageCallback but I’m getting no output.
My OpenGL version is 4.5, I’ve used this command to build my opengl headers/source files: “lua LoadGen.lua -style=func_cpp -spec=gl -version=4.5 -profile=core core_4_5”
The background is clearing in the color I’ve set up, but the two triangles I used to draw don’t appear.
Creating a compatibility context solves the issue.
I’m sorry I don’t know what information I could provide to help you answering my question, I’m creating the context with glfw if that helps.

Here’s a list of the things I’m using:

OS: Windows 7
Graphics card: AMD R9 390
OpenGL version: 4.5
OpenGL loader: glLoadGen
GLSL version: 330 core
Drawing method: VAO/VBO
Windowing framework: GLFW

Is there some check list of things that couldn’t work anymore after switching to core profile?

Thanks for your help.