Locate the Filter to Unblock
Gmail removes an email address or domain from your list of blocked addresses through the Filters and Blocked Addresses page in the settings. The first step is to locate the filter that deletes emails.
Edit the Filter
After you locate the filter that blocks the email address, decide whether to delete it (which stops the action designated for these emails) or to edit it to remove an email address (to unblock messages from that address only).
Delete the Entire Filter
To completely delete the filter and unblock all the email addresses in the From field, remove the filter.
Unblock a Blocked Address
If you use the Gmail Block feature to block senders from their messages, the process of unblocking them is slightly different and more straightforward.
Can’t Unblock the Email Address?
Removing an email address from the filter that blocks those emails — or deleting the filter — is the best way to stop emails from being blocked. However, if after doing so you don’t get emails in your Inbox folder from that sender, there are a few things that you can do
Make Sure There Isn’t Another Filter
There’s a chance that the email that you unblocked is blocked or redirected by a different filter. Do a search for that address on the Filters and Blocked Addresses page in the settings. Another filter may be set up to automatically move those emails to a different folder, in which case you can edit or delete that filter to make sure those messages go to your Inbox folder.
Maybe it Really is Spam
If you were sending the emails to the Trash folder through this filter, those might not be emails you want. So, if the messages don’t go to your Inbox folder after removing the filter, Gmail might be marking these messages as spam.
Force the Issue With a Safelist
Safelisting (typically called a Whitelist, but modern term is Safelist) is another way to make sure your emails are delivered to the Inbox folder is to safelist that email address so that Gmail stops marking those emails as spam. As long as you don’t have a filter that sends the emails to the Trash folder, or to another folder, safelisting will unblock the emails.
More to Consider Before Unblocking
Be careful when deleting Gmail filters that include more than one email address, but especially if the filter blocks a whole domain. Domains encapsulate a lot of email addresses and potential emails. For example, if you block the @spamsite.org domain because it sends spam — and you want to keep blocking those emails — don’t delete the whole filter since that will unblock the whole domain. If you want to unblock all the email address in a filter, don’t edit the filter to remove the Delete it option. Filters must have a setting enabled and an error message appears when all options are removed. It’s best to remove the whole filter to stop automatically deleting emails.