# AUR5003

## Error Message

`AUR5003: Default headers must be a plain object.`

## Description

This error occurs when attempting to configure default headers with a value that is not a plain object. The HttpClient expects default headers to be provided as a simple key-value object where keys are header names and values are header values.

## Common Scenarios

### Passing Non-Object Values

```typescript
// ❌ Wrong: Passing non-object values
client.configure(config => {
  return config.withDefaults({
    headers: 'Content-Type: application/json' // String instead of object
  });
});
```

## Solution

```typescript
// ✅ Correct: Use plain object for headers
client.configure(config => {
  return config.withDefaults({
    headers: {
      'Content-Type': 'application/json',
      'Accept': 'application/json'
    }
  });
});
```


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