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Select Edit/Accounts and then Add / Mail account. Do not select the "Look up mail server details" button. It won't work.
Username: youraccount@ad.helsinki.fi
Change "Server type" to "Exchange Web Services"
Use https://outlook.office365.com/EWS/Exchange.asmx as Host URL.
Click On Authentication, click the box "Override Office365 OAuth2 settings. Use " and use 20460e5d-ce91-49af-a3a5-70b6be7486d1 as Application ID.
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