To verify emails that have gone to quarantine, go to your Quarantine page via the following link: https://security.microsoft.com/quarantine.

Once there, you will see a list of emails that can be sorted and filtered. For specific how-to instructions, please refer to the following links:

• To view your quarantined emails:
  https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/find-and-release-quarantined-messages-as-a-user?source=recommendations&view=o365-worldwide#view-your-quarantined-messages
• Take action on quarantined email
  https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/find-and-release-quarantined-messages-as-a-user?source=recommendations&view=o365-worldwide#take-action-on-quarantined-email

Note: Messages live in quarantine for two weeks before they're permanently deleted. Messages that have expired from quarantine are unrecoverable.