For 2-3 months now I've had this annoying problem.
From my hot Comcast cable connection here at home, I cannot connect to https://owa.mycompany.com/exchange
via Mac/Firefox, my default browser, nor will it pull up with Safari.
At the same moment I CANNOT pull up OWA, I CAN pull up normal sites like Google, CNN and Yahoo.
I CANNOT get OWA via MacBook Pro/Firefox/Comcast
I CAN get OWA via Mac/XPParallels-IE/Comcast
(what I call the XP side of my mac)
I CAN get OWA via Mac/Firefox/Comcast/VPN'd thru my Comcast connection (we use Cisco VPN)
I CAN get OWA via Mac/Firefox/Verizon V640 Aircard
I CAN get OWA via Mac/Firefox/Verizon V640 Aircard/VPN'd.
I CAN get OWA via Mac/Firefox/Sprint Sierra Wireless Compass 597 (new since yesterday)
I've checked my mac parental controls thinking owa was being blocked there, but it is not, is empty.
I also completely bypassed my Linksys WRT300N gateway (plugged my Mac directly into cable modem), again, can get other websites, but not OWA.
My Firefox's proxy settings are all empty-blank (I'm not sure what else to check).
I also logged on for a very time onto my neighbor's unsecure "NETGEAR" WiFi and I cannot pull OWA up that way either, so there must be some setting in my Mac hindering OWA, but allowing OWA site when connected thru Aircard(s) & VPN tunnels.
A fix here will sever 1 more tie to Microsoft, because the simply fix for me is to jump over to XP side when running Parallels & get my email via comcast and IE.