# Not plugged in Learn how to properly initialize the SDK. If you call any method before calling the [`plug`](/reference/sdk/javascript/api/plug/plug) method, you will get the error below: > **Error** > > Croct is not plugged in. To avoid this, ensure you call the [`plug`](/reference/sdk/javascript/api/plug/plug) method at the start of your application, before invoking any other methods. For most applications, the best place to call initialize the SDK is in the [content loaded event](https://developer.mozilla.org/en-US/docs/Web/API/Window/DOMContentLoaded_event) or in the `` tag of your HTML document. See the [Installation page](/reference/sdk/javascript/integration#initialize) for more information on how to initialize the SDK.