when starting powershelluniversal version fromZIP, first-run page stay black

Hello
due to certain security restriction i had some issues starting powershell universal as a service (service cannot access easily internet). while i'm working on a POC, i tried to execute as zip/portable version, where i have a better control to the proxy access.
unfortunatelly, each time i start Start-Process .\Universal\Universal.Server.exe, when i connect to the web page First-run , it start black, nothing appear
http://localhost:5000/first-run

in the console the last lines are 404 with Blazor

[18:27:50 INF] Microsoft.AspNetCore.Hosting.Diagnostics Request finished HTTP/1.1 GET http://localhost:5000/first-run - 200 null text/html; charset=utf-8 1455.5383ms
[18:27:51 INF] Microsoft.AspNetCore.Hosting.Diagnostics Request finished HTTP/1.1 GET http://localhost:5000/_framework/blazor.server.js?v=2026.2.0 - 404 0 null 365.1191ms
[18:27:51 INF] Microsoft.AspNetCore.Hosting.Diagnostics Request reached the end of the middleware pipeline without being handled by application code. Request path: GET http://localhost:5000/_framework/blazor.server.js, Response status code: 404

any suggestion?