To solve the problem do the following: Type in Firefox Browser - about:config Find value "network.automatic-ntlm-auth.trusted-uris" and add bluecoat host name For https authentication is recommended to create Virtual URL and add a different port (not 443 ) https://bluecoatHostName:444 Also check DNS resolution of bluecoat applience ( probably you will need to add it manualy to your DNS serve Read more