If you have Mimecast installed, you will see the Mimecast button at the top of your Outlook. If you do not, please fill out a ticket.
From this tab, you can either search your email archive or check your On Hold Messages.
You will also see On Hold Messages as an email to your Inbox letting you know if you have any emails On Hold.
If you click On Hold Messages, this window will open and they will appear here.
If you click the Search button under the Archive section, this will allow you to search all email.
We started archiving emails October 2020 and going forward all emails that go to your Inbox are automatically archived for you to search, even if they are deleted from your Inbox.
With Mimecast, we have the ability to report emails that will go directly to Mimecast to evaluate and build better filter rules.
You can just right click the email and Report Spam or Phishing.