If you're using an email client like Microsoft Outlook or Mozilla Thunderbird to access your Gmail account, you may need to update your settings to prevent emails from being blocked. Check your email client's settings to ensure that it's configured correctly.
By whitelisting the sender, you're telling Gmail that you want to receive emails from that address, and they will no longer be blocked. gmail unblock email
The Great Gmail Escape: How to Find and Unblock an Email Address You Didn’t Mean to Block If you're using an email client like Microsoft