Introducing students to WordPress - Cannot upload any file!

Hello,

I have three websites running on a paid server, but I’m creating lessons for my high school students on 000webhost.

I’ve spent hours creating detailed lessons on how to build a website using WordPress on 000webhost but I’m now stuck as I cannot upload any file when using “Upload” or “Browse Library”. I’ve logged out and logged back in as my first step. Any help would be great.

Thank you !

Reset/refresh site using general settings menu.

Thank you for your help !