By whitelisting the sender, you're telling Gmail that you want to receive emails from that address, and they will no longer be blocked.
Now that we've covered the reasons why emails might be blocked, let's move on to the solutions. Here are the steps to unblock emails in Gmail: gmail unblock email
You can unblock someone directly through an email they sent, or by finding a past email. By whitelisting the sender, you're telling Gmail that
By doing this, you're telling Gmail that the email is not spam, and it will be moved out of the Spam folder. By whitelisting the sender