There isn't a GitHub Pages site here 404

[itayperry]

I've uploaded a project about 35 minutes ago, changed the branch to 'master', and when I click the
'https://itayperry.github.io/keyboard-piano/' link I get the message: "404 There isn't a GitHub Pages site here".
This always works, and I don't know what happened.

I would love to get some help :)