Microsoft 365 Calendar Sharing

If you are using Microsoft365 to host your email and calendar then you can share a calendar easily with other people in your own company (same Microsoft365 system). But sharing with people outside is a bit tricker. The following approach worked sharing a calendar from a Microsoft365 user to a personal outlook.com email (and calendar) account. I also verified that I could add it to the Calendar app in macOS.

After sharing the calendar, an email will automatically be sent. It will look like this

Clicking on ACCEPT did not successfully add the calendar.  Right click THIS URL and then click COPY LINK. Then go to calendars in outlook.com and click ADD CALENDAR.

Then paste the URL into SUBSCRIBE FROM WEB.

That's it! 

Another thing of note, is that by default when you share the calendar outside of your domain, then you can't grant edit access to the calendar. Maybe there is a way to modify this but I haven't had a need to figure this out.