Finally got things sorted out, and it was the Nginx config that was causing troubles.
The problem was that the $_SERVER['SCRIPT_NAME'] was only returning "index.php" and code needed the "/index.php" to be working properly. Without slash "/" WEB_PA…
I got a bit time to debug further... things almost work (If hacked a bit, real reason not found yet). When loading /fuel/dashboard page it will initialize two XMLHttpRequest from jQx (DashboardController.js). First one /fuel/dashboard/ajax goes ok, …
I tried that also, but it does not change anything.
I couldn't find where the authentication is happening e.g. when getting /fuel/ url after login post? Any hint where to look. I could try to add some traces to see why it does not authenticate even…