Holiday Calendar

I removed the US Holiday calendar that came with my outlook.com account. I later decided that I wanted to resubscribe to the calendar, so I clicked "help" and went to the outlook help page http://windows.microsoft.com/en-us/windows/outlook/calendar-holiday-other. From there I clicked on "United States (English)", which took me to the Import/subscribe page for my calendar. I selected "Subscribe" but received an error stating "There's a problem with the calendar URL that you entered. Please make sure you've entered it correctly and try again." The calendar URL (webcals://calendar.calendar.live.com/calendar/US Holidays/calendar.ics) was autofilled straight from the help page for outlook.com, so it is really odd that I am receiving an error. I have had this problem for a few weeks now and I don't know what else to do. Please help me.