I have a Blazor server app (.Net6) with windows authentication on a Win 2019 Server with IIS. But the username and password dialog is just coming when I open the web page from the google chrome browser directly on the server where the Blazor app is running. When I try to open the page from another PC in the same domain (Chrome, Firefox...), then the page is opening directly without asking username and password.
What could be the reason for that?

I have a Blazor server app with windows authentication. But the username and password dialog is just coming when page is opened from the server side
The reason you are not prompted for a username and password when accessing the Blazor server app from another PC in the same domain is likely due to the integrated Windows authentication and the Single Sign-On (SSO) capabilities of the browser and the server. Here's a brief explanation of how this works:

Integrated Windows Authentication: When using integrated Windows authentication, the browser automatically sends the user's Windows credentials (username and password) to the server without prompting the user for them. This is possible because the browser and the server negotiate the authentication process using various protocols like Kerberos or NTLM.
Single Sign-On (SSO): SSO allows users to authenticate once and then access multiple resources without being prompted for credentials again. In your case, since the client PC and the server are in the same domain, and integrated Windows authentication is enabled, the user's credentials from the client PC's Windows session are automatically passed to the server without requiring a separate prompt.

To ensure that the username and password prompt appears consistently, you can try the following:

Check Browser Settings: Make sure that the browser settings on the client PC are configured to send Windows credentials. In Chrome, go to Settings > Privacy and Security > Site Settings > Additional permissions > Manage permissions. Ensure that the server's URL is listed and set to "Allow" or "Automatic."
Verify IIS Settings: Ensure that the IIS configuration on the server is set up correctly for integrated Windows authentication. Open IIS Manager, select the Blazor server app, and go to the Authentication settings. Make sure that only Windows Authentication is enabled, and other authentication methods like Anonymous Authentication are disabled.
Cross-Domain Considerations: If the Blazor server app is hosted on a different domain, you may encounter additional challenges with SSO due to browser security restrictions. In such cases, you may need to configure your server and browser settings to enable cross-domain SSO.
Clear Browser Cache: Clear the cache and cookies in the browser on the client PC to ensure that any cached credentials or settings are not causing unexpected behavior.

By checking these settings and ensuring that integrated Windows authentication is correctly configured on the server and the client PC, you should be able to consistently prompt for a username and password when accessing the Blazor server app.
