Cancel Fax

Cancel an outbound fax before transmission starts.

Cancellation stops queued preparation and every unsent part, releases the credit reservation, and changes the status to CANCELLED. Repeating a successful cancellation returns the same fax.

Cancellation is unavailable for inbound faxes, completed faxes, and SUBMISSION_UNKNOWN faxes. Pinnacle returns 409 once transmission may have started, even when later parts remain unsent.

HIPAA only: this endpoint exists only in Pinnacle's HIPAA cell and is unavailable at https://api.pinnacle.sh.

Only a fax ID owned by your team is accepted. Unknown IDs return 404.