API Error Response Troubleshooter

Help me troubleshoot an API error I'm encountering.

**API endpoint:** {{ENDPOINT}}
**HTTP method:** {{METHOD}}
**Request headers:**
```
{{REQUEST_HEADERS}}
```

**Request body:**
```json
{{REQUEST_BODY}}
```

**Error response:**
```
HTTP Status: {{STATUS_CODE}}
Response body:
{{RESPONSE_BODY}}
```

**Expected behavior:** {{EXPECTED_BEHAVIOR}}

Please provide:
1. **Error Interpretation**: What does this error code and message mean?
2. **Common Causes**: List typical reasons for this error
3. **Request Analysis**: Check if the request is properly formed
4. **Authentication Check**: Verify authentication/authorization setup
5. **Fix Recommendations**: Specific steps to resolve the error
6. **Debugging Steps**: How to gather more information
7. **Error Handling Code**: Client-side code to handle this error gracefully