My pages have this line in them to point to the manifest.json file:
<link rel="manifest" href="https://www.seekadventure.net/manifest.json">
You can see in the chrome console here it is not being recognized:
Are their special permissions etc that need to be set on the manifest.json file?
Try putting <link rel="manifest" href="https://www.seekadventure.net/manifest.json">
inside the <head>
tags.