Opening HTML file to operate Firebase on MIT App Inventor

I'm making an app on MIT App Inventor with a login page. I created the login page and buttons using an HTML file and coded the buttons using MIT App Inventor (following this code
However, whenever I try to open the HTML file on MIT App Inventor, an error comes up saying "ERR: FILE_NOT_FOUND." The file is uploaded like this:
Is there any way to fix this error? My code is uploaded below. Thank you!

Try with:


(should work with development and compiled, if html file is in assets)