Could be... Depends on the server. Microsoft has a vast network of server farms for various regions.
For instance, my Outlook runs off the
snt server farm in San Antonio. My calendar runs off of the
bay servers in San Francisco. I could possibly have an outage to calendar that doesn't affect email...
Check the address for your calendar (from the url) by copy and paste of the first bit into this site:
Is It Down Right Now? Website Down or Not?
Example: my calendar url shows "https://bay01.calendar.live.com/calendar/calendar.aspx" so I paste the "bay01.calendar.live.com" bit into "Is It Down Right Now?"
Without knowing which server you are asking about, I could not give a definitive answer.
If you need additional help or have more questions or details to share, please join the site so you can reply in this thread. See
this link for instructions on how to join Windows Central.