Wordfence stores a unique identifier called centralSiteId in the wp_wfConfig option. When the identifier belongs to a different Wordfence Central account the plugin blocks any new link attempt. The block appears as an error on the Add New Site screen and prevents the site from appearing in the Central dashboard.
Stale connection data often remains after cloning, migration, or incomplete uninstall. Caching layers may serve the old identifier, extending the conflict across environments.