This policy setting allows you to specify HTTPS server names for which Autodiscover won’t show a warning message when redirecting from HTTP to HTTPS.
By default, when an Autodiscover operation redirects from HTTP to HTTPS, you may be shown a warning message about the redirection.
If you enable this policy setting, you need to specify HTTPS server names, and for those server names, you won’t be shown a warning message. For example, if you enter contoso.com, you won’t be shown a warning message when Autodiscover redirects to https://contoso.com.
If you disable or don’t configure this policy setting, you may be shown a warning message when an Autodiscover operation redirects from HTTP to HTTPS.