If you get an error message when you select the My Day icon from the Office.com header instead of your calendar, this may be because the web browser you're using doesn't allow this feature to appear.
The Intelligent Tracking Prevention in Safari 11.0 (and later) and the Enhanced Tracking Prevention in Firefox 69.0 (and later) can prevent My Day from loading on some of the services in Office.com.
What you can do
To use My Day across Office.com services, we recommend using a web browser that supports this feature, such as the latest version of Microsoft Edge or Google Chrome.