To Do Tasks not Showing in Outlook Calendar

I am in a two person office, and we are using To Do for task management. My partner is having an odd problem. She has logged into our desktop Microsoft office suite and into To Do using the same microsoft credentials; we can see the task list from To Do from within her Outlook at the Tasks Tab;, but the tasks are not showing up in the Task Window we opened her calendar. Mine works fine. The tasks we are trying to popoulate are in a To Do tasklist that we share between us.