This article explains how to block messages from an email address or domain in Outlook.com.

There are a couple of ways to block those spam senders in Outlook.com. The first way is through email that comes into your inbox. To set up a rule in Outlook Mail on the web that deletes all messages from a sender and deletes all current messages from that sender:

Select the Inbox option on the left to view your emails, then double-click on the email to open a message from the sender you want to block.

Select Clean Up from the Outlook Mail toolbar at the top.