ERR_NGROK_SHIP_PUBLISH_TARGET_PUSH_CREDENTIAL_REQUIRED: A KIND publish target needs a 'push_credential_id' - ngrok documentation

What does ERR_NGROK_SHIP_PUBLISH_TARGET_PUSH_CREDENTIAL_REQUIRED mean?

ngrok returns ERR_NGROK_SHIP_PUBLISH_TARGET_PUSH_CREDENTIAL_REQUIRED with this message:

A <KIND> publish target needs a 'push_credential_id'.

Where can I get more help with ERR_NGROK_SHIP_PUBLISH_TARGET_PUSH_CREDENTIAL_REQUIRED?

Email support@ngrok.com and include the error code.