Permissions have changed due to a recent update, but the problem specification has not been edited to reflect this.
PHP files and
config.json now need to be set
chmod 640, even though the problem specification says
chmod 600. Also, all directories need a minimum of
chmod 711, which your
public directory has currently, but others like
views do not.
chmod -R seems expedient, but it is a bad habit to get into. It may help to get the site to load, but it always leaves you with unneccessary security holes. Luckily, there is a better way.
I've consolidated my advice from several sources into this definitive guide on the CS50 Reddit.
Please read the guide! I hope it helps you.
If you get your permissions straightened out, let me know by clicking the green check mark. Otherwise this question will always remain marked as unanswered, and it will haunt the forum forever as a Zombie Question.