ERR_NGROK_SHIP_DOMAIN_CERT_ID_REQUIRED: The 'cert_id' field must not be empty when 'cert' is 'uploaded' - ngrok documentation

What does ERR_NGROK_SHIP_DOMAIN_CERT_ID_REQUIRED mean?

ngrok returns ERR_NGROK_SHIP_DOMAIN_CERT_ID_REQUIRED with this message:

The 'cert_id' field must not be empty when 'cert' is 'uploaded'.

Where can I get more help with ERR_NGROK_SHIP_DOMAIN_CERT_ID_REQUIRED?

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