XF 2.2 Any idea on how to fix this error? "failed to load resource: the server responded with a status of 503 () webmanifest.php:1"

[Global96]

So I had some issues for a while which caused "Oops we ran into some problems" errors randomly on the home screen (with 403 errors in the browser console). I disabled WAF which seems to have fixed this (it has been about half an hour and it hasn't reoccurred). However I still see these errors in browser console: "failed to load resource: the server responded with a status of 503 () webmanifest.php:1"

All I can find is that webmanifest has something to do with PWAs.