ERR_NGROK_440: Uploaded certificates are not allowed for domains owned by ngrok

What does ERR_NGROK_440 mean?

ngrok returns ERR_NGROK_440 with this message:

Uploaded certificates are not allowed for domains owned by ngrok.

Troubleshoot ERR_NGROK_440 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.