Hi Hailstorm,
Sorry for my misunderstanding. I’d like to collect the following information in order to narrow down the problem:
1. What subscription of Office 365 you are using?
2. Where have you subscribed to these calendars? Please let me know the steps you have done.
3. Some screen shots which will help to clarify the problem.
Meanwhile, the following link talking about viewing and subscribing to Internet Calendars in Outlook is for your reference:
office.microsoft.com/.../view-and-subscribe-to-internet-calendars-HA102534443.aspx
Thanks,
Nancy Xie