No App Install Prompt and Cache

Hello, I just installed the Super PWA and to my demise, I found that no App Install Prompt appears at the bottom of my mobile page. Yes, I am using a compatible mobile device with the latest Google Chrome installed.

So I tried adding it to “Home Screen” manually from the chrome setting instead. I was able to add the icon to the home screen that way, and there is that splash screen when I opened the app via the icon, but when I visited the site and browse pages I have visited before in offline mode, it didn’t serve me the cached page but is telling me that I am offline instead. No, it didn’t even show the supposed “offline page” I set in the plugin…

Am I doing something wrong or is there something in my site blocking the pwa from working, or is has to do with my mobile setting…

The page I need help with: [log in to see the link]