By default, when you remove a user from the suppression list of an email id or domain using the suppression list feature available in the panel, all emails to the same email id or domain will be processed instantly. Usually, all changes which you do within the suppression list from the panel are replicated on a real-time basis however at times you might observe a delay of around 1-2 mins max.

In case, if you are doing changes to the suppression list of your Netcore email API account using suppression API, it takes around 3 hrs to sync the same data in a production environment. As a result of which you might observe some delay in syncing the data in a production environment.