What tools can I use to diagnose 403 errors when accessing DeviantArt content through CloudFront?

Use CloudFront access logs (Enable detailed logging) and CloudWatch to monitor for errors and get insights into requests failing with 403 status codes. Use browser developer tools to examine the request headers. Compare the request headers generated by your browser to those being sent to CloudFront. Utilize tools like `curl` or `wget` to test image retrieval, explicitly setting the `Referer` and other headers to see whether it helps. Also, check the CloudFront distribution and origin configuration.