suppressions verifiedcriticalWritten by the Hub
Suppression list
Addresses and domains that are failed immediately, with a chosen code, checked at the moment of delivery.
In detail
Because the check happens at delivery rather than at acceptance, adding an address stops mail that is already queued — which is what makes it the right tool after a complaint or a hard bounce. Undocumented as a table, though the feature is described and has its own REST endpoint. For Hub this is the natural home of the shared blacklist the warm-up module already maintains: a hard bounce recorded once should stop that address on every node, and this table is cluster-wide by construction.