I've been helping my neighbor try to resolve an issue which recently cropped up on his new Apple iMac. He can browse the internet just fine, but when he tries to visit a particular site (http://mbeweb.mbe.com), the browser just reports 'Loading' until it gives up and times out.
The site should show a HTTP Basic Authentication login prompt, but it doesn't, in any browser on that iMac. Other sites that require Basic Authentication work fine.
This happens no matter what browser he uses under Mac OS X (Safari 4, Firefox 3.5, Opera, and iCab) and it seems to be only this site (obviously we haven't tried all of the websites available on the internet). From his same home network, he can access the site from his Windows laptop and I've brought my MacBook Pro over and verified that I can connect as well (as can my iPhone).
To make it even stranger, if he launches VMware Fusion on that iMac and attempts to connect to that site using IE or Firefox under Windows XP, he gets the exact same behavior. Other sites work well in Windows.
This happens for a completely new user as well.
From the Terminal, I can telnet to the site (telnet mbeweb.mbe.com 80) and it connects fine and I can issue "GET /index.html HTTP/1.1" and the web server responds with valid HTML and a 401.2 Unauthorized HTTP Error.
I've tried flushing his cache (dscacheutil -flushcache), rebooting the iMac, clearing the browser caches, cookies, stored logins, etc. The issue seems to be localized to this iMac.
He said that it used to work fine. We've contacted the site administration and they explained some recent changes they've made (switched to SharePoint and all of the old links now redirect to it) but verified that they're able to access the site from both Windows and Mac machines (though they did note they had difficulty using Windows running under a VM).
I'm about ready to back-up his machine and re-image it, but perhaps someone has a better suggestion that I haven't tried yet?