Time format in Outlook calendar and emails

Outlook version
Outlook 2016 64 bit
Email Account
I'm using Windows 10 and Outlook in Office 365 (subscription version, not cloud-based). I've changed the time format to 12-hour (AM/PM) time in both Settings and Control Panel. That successfully changes the format in the Windows task bar, but not in Outlook emails or calendar. How do I change these to 12-hour format? Everything I've seen in Microsoft Community and elsewhere says use Settings or Control Panel, but that has not worked for me.

Grateful for any ideas.