Accidentally blocked a newsletter, a colleague, or a friend? Or perhaps you resolved a dispute and are ready to receive emails from a previously blocked sender again. In Gmail, blocking a sender automatically diverts their emails to your Spam folder, meaning you will never see them in your primary inbox.
If you still have an email from the person in your inbox or spam folder, you can unblock them directly from the message: Open the message from the blocked sender. unblock mail in gmail
This is the most common way to manage blocked contacts. Accidentally blocked a newsletter, a colleague, or a friend
This feature allows users to unblock emails from specific senders that were previously blocked in their Gmail account. Accidentally blocked a newsletter