I've just completed a project and everything is working perfectly except one nagging issue. When I try to access the project's website from an icon added to my Android home screen either from Firefox or Chrome, I get the 404 File Not Found error. When I try to add the site to my home screen from Edge, the option is greyed out and not available. I am able to access the website from each browser directly, it's just not working from the home screen icon. I'm sure it's something simple that I did not do, but I am unsure what that might be. If anyone knows what I may have missed, I would appreciate you pointing me in the right direction.
I figured it out. In the site.webmanifest file in the root of my site's public directory, I had a bad "start_url". Here is some sample code for others who may run into this: