ERR_NGROK_4021: This account cannot be deleted because it has an unpaid invoice

What does ERR_NGROK_4021 mean?

ngrok returns ERR_NGROK_4021 with this message:

This account cannot be deleted because it has an unpaid invoice. Contact support@ngrok.com for help deleting this account.

Troubleshoot ERR_NGROK_4021 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.