ERR_NGROK_601: This credential is your tunnel token and cannot be deleted, only rotated

What does ERR_NGROK_601 mean?

ngrok returns ERR_NGROK_601 with this message:

This credential is your tunnel token and cannot be deleted, only rotated.

Credential ID: <ID>
Description: <DESCRIPTION>

Troubleshoot ERR_NGROK_601 with your AI agent. Connect it to the ngrok MCP server, then ask what caused the error and how to fix it.

Why does ngrok return ERR_NGROK_601?

You tried to delete the default authtoken for your account, which ngrok calls your tunnel token. You can’t delete this authtoken, but you can rotate it.

How do I fix ERR_NGROK_601?

To rotate your default authtoken:

Go to Your Authtoken in the dashboard.
Click Reset Authtoken.
Confirm the reset. ngrok revokes the old authtoken and shows you a new one.
Update every agent, SDK, and Kubernetes Operator that used the old authtoken. For the ngrok agent, run ngrok config add-authtoken <NEW_AUTHTOKEN>.

Agents, SDKs, and Kubernetes Operators that still use the old authtoken can’t connect after the reset, and you can’t undo it. To manage authtokens you can delete, create additional authtokens or use the Credentials API.

Where can I get more help with ERR_NGROK_601?

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