Error with Gantry and theme


I’ve just installed Gantry to test it and create themes. I’ve installed also Hydrogen and Helium theme that looks to be needed.
But I have this error : RuntimeException (400)
Template “blog.html.twig” is not defined. when I try to go to the site, even if I don’t do any modifications, with these 2 themes only.

Any idea please ? I’m a beginner with Gantry, I never used it before…


Ok, find the solution. I had to modify the template of the page…