Can’t access calendar.live.com. All other live.com addresses work.

So, having a strange issue here and it's affecting every computer at my location. I can log into my live account, check my mail, etc, however if I try to view my calendar (calendar.live.com), I get Page Cannot Be Displayed. This has been going on for over a week now. If I take my laptop next door, or any other location, it works fine. I installed a free VPN to test with and as long as that VPN tunnel is active, calendar loads up fine. Since Microsoft doesn't seem to have a technical email for this kind of stuff, I thought I'd post here. I feel it's either calendar.live.com inadvertently blocking my WAN IP, or it's my ISP blocking connections to that site (yet nearby locations on the same ISP can access it fine). It's definitely not an internal issue as I've checked our equipment. Anyone have an idea of where to go from here?