Cancellation changes a future message before dispatch begins. It does not recall a message that has already started delivery.
Check the current state
Read the message using a protected account or full-access key and confirm that no dispatch attempt has begun. Keep sending-only credentials limited to their intended operations.
A stale dashboard view is not enough. The cancellation and worker claim must coordinate through the durable message record.
Use the explicit cancel operation
Submit the documented cancellation request with the message identifier. The API retains the accepted record and its quota reservation according to the current contract.
If the message is already in flight, the cancellation cannot recall it. Preserve the provider outcome and do not report it as canceled.
Create a new message only for a new action
A changed appointment or order can justify a new customer event under your application’s rules. Do not reuse a canceled event or generate a new identifier solely to bypass a prior decision.
Record the cancellation reason and follow the replacement message separately through delivery evidence.
Continue with a related guide
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Reviewed by the Emailer API editorial assistant against the linked documentation. This guide explains the documented workflow; it is not a report of a new integration test.