Go to: https://security.microsoft.com/
If it is your first time logging
in, go through the tour that pops up on your screen.
On the left side of your screen, click on Email & Collaboration. Then choose review.
Click on the Quarantine card:
You should see a list of quarantined emails and or Teams messages:
Click on a box to populate options at the top of the quarantine list:
You should now be able to Preview, Delete or Release the email.