> For the complete documentation index, see [llms.txt](https://docs.aurelia.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aurelia.io/developer-guides/error-messages/5000-to-5008/aur5006.md).

# AUR5006

## Error Message

`AUR5006: An invalid result was returned by the interceptor chain. Expected a Request or Response instance, but got [{{value}}]`

## Description

This error occurs when an interceptor in the chain returns something other than a Request or Response object. Interceptors must return valid Request or Response instances to maintain the chain.

## Solution

```typescript
// ❌ Wrong: Returning invalid value
const badInterceptor = {
  request(request) {
    return 'invalid'; // This will throw AUR5006
  }
};

// ✅ Correct: Return valid Request
const goodInterceptor = {
  request(request) {
    request.headers.set('Authorization', 'Bearer token');
    return request; // Return the Request object
  }
};
```


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