If your users wanted to use the My Inbox or My Calendar webparts on any page, they first need to configure the property pane of the web part.

You’ll get the lovely “404 – File or directory not found.” error message if you input the wrong URL address.

Give this a go:

Mail server address

• https://<yoursite>/owa

OR (depending on how you have your Exchange server configured)

• https://<yoursite>/exchange

Mailbox

• usersemail@<yourdomain>.com

Apply + OK.