How to fix Ngrok Custom Subdomain Error when using a free, static domain

[hayata-suenaga]

When you create a free, static domain on the Ngrok dashboard, you get a URL that resembles the one below:

https://<your-static-domain>.ngrok-free.app

I want to use this static domain when running an agent using the JavaScript SDK.

  const url = await ngrok.connect({
    addr: 5001,
    authtoken: process.env.NGROK_AUTHTOKEN,
    subdomain: your-static-domain,
  });

However, I encounter the following error when I attempt this:

failed to start tunnel: Custom subdomains are a feature on ngrok's paid plans.

How can I resolve this issue and use the free, static domain with the JavaScript SDK?