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In Outlook
Open the mail in outlook (at least in the read panel)
A new button is available in your toolbar: "the report message". Click on it
Based on the content of the message, select of it's pure spam (junk) a phishing attempt or "not junk" if you estimate is was incorrectly flagged as spam.
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Click on the 3 dots icon and select the appropriate option
If you have opened the mail in full screen, the option "junk" is also available in the toolbar.
