Web App not working

It's now seven days since I can not use the WebApp through the site. I can login on the game (Xbox Series X), I can login on the mobile Companion App. I can list players on the market on both.
I tried:
- cleaning the cache
- using a private tab on my browser
- switching to different browsers
- switching different connections (two different Wi-Fis, one ethernet link)

I always get the same error on screen: "EA Account Server Unavailable. There was a problem connecting to the EA Servers. Please check your internet connection and try again."

I also made various reboots on my pc, internet is working perfectly both with or without VPNs. Just the FC WebApp is not working.

The WebApp works if I try and connect on different devices.

How the heck does this work? Out of the blue, I can't use the WebApp anymore?

[I hope people here can help me better than "EA Customer Service", as they can't even tell the difference between WebApp and WhatApp...]