User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; InfoPath.1; .NET CLR 4.0.20506; OfficeLiveConnector.1.4; OfficeLivePatch.1.3; InfoPath.2) Build Identifier: Mozilla/5.0 (Windows NT 5.1; rv:2.0b5) Gecko/20100101 Firefox/4.0b5 I tried going to gmail.com and bugzilla.mozilla.org both activate the loading bar in the lower right corner but immediatly disapears as if the website is loaded. I am currently connecting through a squid proxy configured under a .pac file. So far any other website works fine slashdot,google,etc Reproducible: Always Steps to Reproduce: 1. enter "gmail.com" 2. hit enter 3. event happens Actual Results: Page doesn't load Expected Results: shows the gmail page about:buildconfig Source Built from http://hg.mozilla.org/mozilla-central/rev/58575263536b Build platform target i686-pc-mingw32 Build tools Compiler Version Compiler flags d;D:\mozilla-build\msys\mozilla-build\python25\python2.5.exe -O e;D:\mozilla-build\msys\builds\moz2_slave\win32_build\build\build\cl.py cl 14.00.50727.762 -TC -nologo -W3 -Gy -Fdgenerated.pdb -DNDEBUG -DTRIMMED -Zi -Zi -UDEBUG -DNDEBUG -GL -wd4624 -wd4952 -O1 d;D:\mozilla-build\msys\mozilla-build\python25\python2.5.exe -O e;D:\mozilla-build\msys\builds\moz2_slave\win32_build\build\build\cl.py cl 14.00.50727.762 -GR- -TP -nologo -Zc:wchar_t- -W3 -Gy -Fdgenerated.pdb -wd4800 -DNDEBUG -DTRIMMED -Zi -Zi -UDEBUG -DNDEBUG -GL -wd4624 -wd4952 -O1 Configure arguments --enable-application=browser --enable-update-channel=beta --enable-update-packaging --enable-jemalloc --enable-tests --enable-official-branding

Is this happening on all HTTPs supporting Sites equally?

it seems so I can't even get into my bank login page(and gmail I forced to loging as HTTPS)

Almost certainly bug 592197. Please check beta 6 once it comes out? The bug should be fixed in it.