Sometimes it happens that accessing Subversion (SVN) or some services behind Apache or NGINX with basic authentication shows empty page and 401 unauthorized error. Apart from other reasons one of the most frequent reasons why it happens is actually setting in the browser, which prohibits usage of basic authentication. If there are no other authentication options on server available, then server actually delivers empty page or shows 401 (Unauthorized) status code and error message.
Workaround for Edge browser on Windows to allow support for basic authentication is to import following Registration Entries (.reg) files into Windows registry:
EnableBasicAuthenticationInEdgeSettingsRegistry.reg
Import it by double clicking in Windows and it will enable basic authentication for Edge browser.
Then restart Edge browser and you shall be asked for password.