Error codes
recipient_suppressed
HTTP status: 422
What happened
The recipient is on this account's suppression list or on the global suppression list. Account entries come from a hard bounce, a complaint, or a manual block.
How to fix
Remove the address from your account list when it is safe to send to. A global suppression is not in that list and cannot be deleted through the API. Contact support if you think the suppression is wrong.
Source: docs/errors/recipient_suppressed.md.