ERR_NGROK_9028: You must specify a domain name for a internally bound endpoint

What does ERR_NGROK_9028 mean?

ngrok returns ERR_NGROK_9028 with this message:

You must specify a domain name for a internally bound endpoint.

Troubleshoot ERR_NGROK_9028 with your AI agent. Connect it to the ngrok MCP server, then ask what caused the error and how to fix it.

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