ERR_NGROK_202: The API authentication you specified does not look like a valid credential - ngrok documentation

What does ERR_NGROK_202 mean?

ngrok returns ERR_NGROK_202 with this message:

The API authentication you specified does not look like a valid credential. API keys and instructions are available on your dashboard: https://dashboard.ngrok.com/api-keys

Where can I get more help with ERR_NGROK_202?

Email support@ngrok.com and include the error code.