Block Senders in Outlook Web App

This article describes how to automatically mark senders as junk through the Outlook Web App interface. If you need to safelist a sender, see Safelist senders in Outlook Web App.


  • Applies to: User
  • Difficulty: Easy
  • Time needed: Approximately 15 minutes for change to complete
  • Tools Required: Mailbox access

For more information about prerequisite terminology, see Cloud Office support terminology.

Block Senders

Warning: Outlook Web App does not include a setting to reject senders. It only automatically marks blocked senders as junk. Administrators can reference Blocklists in Microsoft Exchange for instructions on how to reject senders.

  1. Log in to your Exchange mailbox at

  2. Click the gear icon in the upper right-hand corner, and then select Options from the drop down menu.

  3. In the Options menu, click Mail > Accounts > Block or Allow.

  4. Enter the email address or domain of the sender that you want to automatically mark as junk.

  5. Click Save.