An email address had been added to Local Good Sender list, but it is still being blocked. The Message Audit Log (MAL) record for the message shows System allowed email address or domain and User Reject as the verdict. And Delete Message as the action taken.
The sender address or domain can be seen in the recipient's Personal Bad Sender list.
The personal / end user Good and Bad Sender list has a higher priority than Local Bad and Good Sender list. The personal/end user settings overrides Local Good Sender list and Local Bad Sender list.