This article describes how to access and manage your emails blocked and safe senders lists within Outlook.
...
When complete select Apply and OK to close the window.
If you are using the Outlook 365 Web App online sign in to https://login.microsoftonline.com/ using your SU credentials
On the right hand side select the gear icon to access settings then choose View all Outlook settings
In the settings window under Mail select Junk email.
Click Add below Blocked senders to add users to the blocked list or under Safe senders to add to the safe recipient list.
To remove and email address highlight the email to be deleted and select the trash icon to the right
