UE4 4.14.3 not launching

Hello,

I just recently installed High Sierra to my Mac Book Pro and 4.14.3 isn’t launching. It was launching and functioning fine yesterday with El Capitan, but my class didn’t want me using that version. They wanted me to upgrade to regular Sierra but they didn’t have it anymore. I was just wondering what’s going on and if there is anyway to fix this and so I wouldn’t have to start over on my project.

Thank you.