No. Google does not send a notification to the person when you block or unblock them.
If you still have a message from the sender (even if it's in your Spam folder), this is the fastest way to restore communication: on your computer or mobile app. Open an email from the sender you want to unblock. how to unblock people in gmail
(the three vertical dots) in the top right corner of the message. Select "Unblock [Sender Name]" from the dropdown menu. Confirm the action in the pop-up window. How to Unblock via Gmail Settings (Desktop Only) Open an email from the sender you want to unblock
By following these steps, you can easily restore communication lines and ensure you never miss an important email again. Confirm the action in the pop-up window
If emails from a contact are still going to spam after you unblocked them, you may have a stray filter set up.
Note: If you cannot find an old email from them, check your folder, as emails from blocked senders are automatically routed there.