Follow the guidance in this topic to learn how to find and release messages that were quarantined instead of being delivered to you.
To see your spam-quarantined messages in quarantine, do the following:
Sign in, using your Office 365 credentials (user ID and password).
On your Quarantine page, you'll see a list of any messages that were sent to you, but were identified as spam and redirected to the quarantine.
Sort or search messages as needed.
Double-click a specific quarantined message to view details about it, and take actions. If the message wasn't actually spam, you can release it (have it sent to your mailbox) and report it as not junk to the Microsoft Spam Analysis Team.
Or you can select one or more messages, and then choose an action from the Actions drop-down list.