CloudFront distribution errors.

Amazon CloudFront is a content delivery network (CDN) service provided by AWS. It's used to securely deliver content, such as web pages, videos, images, and other files, to users with low latency and high data transfer speeds. If you encounter errors with your CloudFront distribution, it's important to identify and address the issue promptly. Here are some common CloudFront distribution errors and how to resolve them:

1. Access Denied (403 Forbidden):
   • Cause: This error occurs when a user attempts to access content they do not have permission to view.
   • Solution:
     • Check the permissions on the underlying S3 bucket, or the origin server if you're not using S3, to ensure the user has the necessary access.
     • Verify that CloudFront is correctly configured to forward headers, cookies, or query strings if needed for authentication.
2. Invalidation Errors:
   • Cause: Invalidation errors occur when there are issues with invalidating cached content in CloudFront.
   • Solution:
     • Ensure you're using the correct path pattern in the invalidation request.
     • Verify that the objects you're trying to invalidate exist in the distribution.
3. Origin Server Errors (5xx):
   • Cause: These errors indicate an issue with the origin server (e.g., an EC2 instance, S3 bucket, or custom origin) that CloudFront is trying to fetch content from.
   • Solution:
     • Check the health of your origin server and verify that it's reachable from CloudFront.
     • Review server logs for errors or investigate if there are any issues with the application on the origin.
4. Distribution Not Enabled:
   • Cause: The CloudFront distribution may not be enabled or maybe in the process of being deployed.
   • Solution:
     • Verify that the distribution is enabled in the CloudFront console.
     • Wait for the distribution to fully deploy if it's currently in progress.
5. Invalid SSL Certificate:
   • Cause: This error occurs if the SSL certificate used for your CloudFront distribution is not valid or is expired.
   • Solution:
     • Ensure that the SSL certificate associated with the distribution is valid and properly configured.
     • Verify that the certificate is issued by a trusted Certificate Authority.
6. Access Logs Not Enabled:
   • Cause: You may not be seeing access logs in your S3 bucket, even though logging is enabled in the CloudFront distribution.
   • Solution:
     • Confirm that the S3 bucket specified for access logs exists and is correctly configured.
     • Ensure that the necessary permissions are set for CloudFront to write logs to the specified S3 bucket.
7. CORS (Cross-Origin Resource Sharing) Errors:
   • Cause: This error occurs when a web application hosted on one domain attempts to access resources on a different domain, and the server does not allow it due to CORS policies.
   • Solution:
     • Adjust CORS settings on your origin server or S3 bucket to allow the necessary domains to access the resources.
8. 404 Not Found Error:
   • Cause: This error indicates that the requested resource could not be found.
   • Solution:
     • Double-check the requested path and ensure that the resource exists on the origin server or S3 bucket.
9. Missing or Invalid Default Root Object:
   • Cause: If you've configured a default root object (e.g., index.html) and if it's missing or inaccessible, it can result in errors.
   • Solution:
     • Verify that the default root object is present in the origin.
10. Cache Behavior Misconfiguration:
    • Cause: Incorrect settings for cache behaviors can lead to unexpected behavior or errors.
    • Solution:
      • Review the cache behavior settings in your CloudFront distribution and ensure they align with your application's requirements.

Always consult AWS documentation and use the CloudFront console or API to check and modify settings as needed. Additionally, consider using CloudFront monitoring and CloudWatch metrics to gain insights into the performance and health of your distribution.