TTF_OpenFont returning NULL

TTF_OpenFont() returns NULL

I have the same problem, TTF_OpenFont returns NULL and with an error.

    TTF_OpenFont("/absolute/path/to/SourceSansPro-Black.ttf", 25);
    std::cout << TTF_GetError() << std::endl;

And I get the "Couldn't load font file"

• The .ttf chmod is 777
• I tried running the program with root

I run out of ideas.