That page actually is a frame around a different site ([https://client.psms-cpa.com/]). You can load framed pages in a new tab by right-clicking the error page, expanding the "This Frame" submenu, then Open Frame in New Tab. Firefox 40 no longer shows the basic authorization login prompt for a framed page that is hosted on a different server. This is to protect you from accidentally giving your credentials for the outer page to an attacker. One option is to used the framed page directly, but if you prefer to disable this new protection, there is an option to do that. Of course, please be suspicious of this prompt appearing on other sites. (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button promising to be careful. (2) In the search box above the list, type or paste '''auth''' and pause while the list is filtered (3) Double-click the '''network.auth.allow-subresource-auth''' preference and edit the 1 to a 2 and click OK * 1 shows the login dialog only for framed pages, images, etc., ''hosted on '''the same site''''' * 2 allows the login dialog for framed pages, images, etc., ''hosted on '''any site''''' That should take effect the next time you reload the outer page (your original address).

Thanks for your help.