When you visit a site with basic authentication in Edge the browser shows instead of the authentication pop up an error.
“Unauthorized. This server could not verify that you are authorized to access the document requested. Either you supplied the wrong credentials (e.g., bad password), or your browser doesn’t understand how to supply the credentials required.”
Check the Edge policies at edge://policy/ which shows basic authentication is not an option in the auth schemes
For testing purposes it’s an option to edit a registry value to allow basic auth.
start regedit.exe
browse to the key HKLM\SOFTWARE\Policies\Microsoft\Edge\AuthSchemes
Edit the value to: basic,ntlm,negotiate
click reload policies at the Edge policies site edge://policy/
Basic auth is now added to the AuthSchemes and the authentication popup will appear again.
more information: Microsoft Edge Browser Policy Documentation | Microsoft Learn