Open Outlook on your Mac.

A window will appear listing all blocked email addresses. Select the one you wish to unblock.

Select Blocked Senders .

Tap the Junk Email folder (you may need to scroll down the folder list).

Find an email from the sender you want to unblock. Right-click that email.

Choose Mail > Junk email .

Click the Settings (Gear icon) in the top-right corner.