Before you fix the problem, it helps to know where the block is actually happening. Outlook generally uses two different systems:
To unblock a sender in Outlook, you generally need to access your settings and remove the specific address or domain from your "Blocked Senders" list. Once removed, future emails from that sender will be delivered directly to your inbox instead of your Junk folder. How to Unblock Senders by Platform unblock sender outlook
Whether you were trying to stop a flood of spam or simply clicked the wrong button, unblocking a sender in Microsoft Outlook is a straightforward process. However, the exact steps depend on which version of Outlook you are using (Classic desktop, the new Outlook, or Outlook on the web). Before you fix the problem, it helps to