ERR_NGROK_SHIP_START_COMMAND_NOT_ALLOWED: The 'start_command' field is not supported for repository apps - ngrok documentation

What does ERR_NGROK_SHIP_START_COMMAND_NOT_ALLOWED mean?

ngrok returns ERR_NGROK_SHIP_START_COMMAND_NOT_ALLOWED with this message:

The 'start_command' field is not supported for repository apps. Set the run command in the app's build settings.

Where can I get more help with ERR_NGROK_SHIP_START_COMMAND_NOT_ALLOWED?

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