ERR_NGROK_398: The ID header cannot be removed without specifying a replacement

What does ERR_NGROK_398 mean?

ngrok returns ERR_NGROK_398 with this message:

The <ID> header cannot be removed without specifying a replacement.

Troubleshoot ERR_NGROK_398 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.