Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi randomUQ,
Thank you for your time and patience.
According to your description, I've done my test. Let me share with you my test here. I added my Office 365 for Business work account to the Mail app.
Once added to the Mail app, calendar and event were synced successfully as below.
However, I was not able to find the Task feature in Mail app.
You may set up your account referring to Set up email in the Mail app for Windows 10. And if you still encounter the same issue, since we are online support for Office 365 for Business, to better support you, I would suggest that you should post a thread in the Categories > Windows > Apps on Windows 10 > Mail/Outlook Mail. Thank you very much for your understanding!
Sincerely,
Qian