ERR_NGROK_3212: Tunnel HOSTNAME has multiple bindings but no binding was specified

What does ERR_NGROK_3212 mean?

ngrok returns ERR_NGROK_3212 with this message:

Tunnel <HOSTNAME> has multiple bindings but no binding was specified

Troubleshoot ERR_NGROK_3212 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.