KI 2268 I accidentally added an email address to my block list in Outlook
Outlook allows you to mark a sender of email as blocked. If you do this, you will not see email from that sender again in your inbox. This is a great feature that allows you to manage spam messages or other unwanted email. However, if you accidentally add an address to the list that you _want_ to get email from, you will need to remove it.
Microsoft provide instructions on how to unblock senders which can be found here.