Thanks for all the checks you have made so far.
The pop up you are seeing is unrelated to the issue at hand so lets figure out one thing before the other.
I know you mentioned you have reinstalled the plugins, however when you uninstall/remove them, make sure that the associated folders are removed also.
- Microsoft Store Version: Open your File Explorer and delete the folder located at:
%LocalAppData%\Packages\Microsoft.Limitless_8wekyb3d8bbwe\LocalState\WASM\MSFS2020\navigraph-efb-simbriefapp - Steam Version: Open your File Explorer and delete the folder located at:
%AppData%\Microsoft Flight Simulator 2024\WASM\MSFS2020\navigraph-efb-simbriefapp
Also, please try connecting your computer to the internet using your mobile phone connection in tether mode. This will help isolate the ISP in case they are blocking a connection.
Onto the Microsoft Store popup, firstly, make sure you set Google Chrome as your default browser.