Firebase hosting: Needs Setup
I had the same problem, I was able to resolve it by toggling the DNS Status on cloudflare from DNS and HTTP Proxy (CDN)
to just DNS
on the two A records
It started working right away. Hope that helps!
The proper solution, ie without disabling Cloudflare for the site, is to use Full SSL for your domain/subdomain.
You can either choose Full SSL for all your domain entries, or set up a Page Rule for a specific subdomain, in your case, use "inv.agsft.com/*"
Source: https://community.cloudflare.com/t/flexible-ssl-redirect-loop-with-google-firebase/2063/3, which in turn points to https://support.cloudflare.com/hc/en-us/articles/115000219871-Why-does-Flexible-SSL-cause-a-redirect-loop-
Had the same issue and this solved the redirect issue. Firebase will however still report the domain as "Needs setup", for that I have no solution, but it does not affect the functionality of the hosting.
For the people that is using Namecheap, This configuration worked for me.