timo to-do.live.com and to-do.office.com are in fact two different services, that can be used side by side. Diarium allows for connecting with both of them (depending on credentials - because Microsoft somehow redirects the auth-request accordingly).
Diarium also queries the tasks from the service, but it assumes, that the link for showing the task is always "to-do.live.com" - which isn't the case, if one connects via a business-account (which is great, by the way!).
The challenge might be to tell, which URL to use to open the link 🤔 .
Attached are two screenshots to clarify the difference;


Regards, Michael