User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; InfoPath.3) Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b5) Gecko/20100101 Firefox/4.0b5 When I type or copy/paste a secure (HTTPS) URL into Firefox's Address bar, and navigate to that URL, Firefox does not load the page. This also happens if following a HTTPS hyperlink from a standard (non-secure) HTTP page. Reproducible: Always Steps to Reproduce: 1. Type or copy/paste a HTTPS URL into Firefox's address bar. 2. Attempt to navigate to said URL. Actual Results: Firefox does nothing Expected Results: Firefox navigates to secure URL This issue was not present in beta 4.

Are you behind a NTLM Proxy?

Note that I had to file this bug report from another browser (in this case Internet Explorer) as Firefox is unable to browse to any secure sites, including Bugzilla! (In reply to comment #1) > Are you behind a NTLM Proxy? Yes.

Hmmm, I did search for this bug before posting, but I didn't realise it's an NTLM-only problem. Thanks guys, guess I'll just have to wait for beta 6.