ERR_NGROK_5307: The domain "DOMAIN" specified in the IdP-initiated RelayState is not attached to the endpoint configuration "ECID"

What does ERR_NGROK_5307 mean?

ngrok returns ERR_NGROK_5307 with this message:

The domain "<DOMAIN>" specified in the IdP-initiated RelayState is not attached to the endpoint configuration "<ECID>".

Troubleshoot ERR_NGROK_5307 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.