Using older versions of Outlook for Mac for personal email and calendar
Dear P.Sullivan_08,
May I please confirm that whether you added more than three calendars?
According to my test, you can view up to 3 calendars in Side-by-Side view at a time. If you have more than 3 calendars selected, you will not be able to view it in side-by-side view. You must delete calendars until you have 3 or fewer selected to view the calendars in Side-by-Side view again.
If you want to look for the information of calendar, you can also try following steps to check the result.
Open the outlook for Mac>click calendar button>select the calendar you want to view>find the view option at the top and click on it>choose list (Then you can view the information in the calendar as a list.)
Maybe you can submit feedback: open the outlook>find the Help button in the top>choose give feedback
Please feel free to let us know if you have any questions about this. I’ll be happy to help.
Best regards,
Kerry