Lambda@Edge Function Not Triggering on CloudFront Viewer Request

What's Wrong: I have a Lambda@Edge function that is supposed to trigger on a CloudFront 'Viewer Request' event. The function is designed to perform A/B testing by routing traffic to one of two S3 buckets. However, the function is not being triggered when I access my site via CloudFront or directly through the domain name.

Steps Taken for Troubleshooting:

• Verified that the Lambda function is deployed and associated with the correct CloudFront distribution.
• Checked the CloudFront behavior settings to ensure that the Lambda function is set to trigger on 'Viewer Request'.
• Created CloudFront invalidations multiple times to clear the cache.
• Manually invoked the Lambda function from the AWS Console, and it executed successfully.
• Checked CloudWatch logs and metrics; no logs or metrics are being generated for the Lambda function.
• Reviewed the IAM role and trust policy for the Lambda function; it allows edgelambda.amazonaws.com and lambda.amazonaws.com to assume the role.
• Deployed a simple test Lambda function that logs a message and associated it with the same CloudFront distribution. This test function also did not trigger.

Support Needed: Please help me identify why the Lambda@Edge function is not being triggered.

• Are there any additional logs or metrics that can be accessed to diagnose the issue?
• Is there any misconfiguration in my CloudFront distribution or Lambda function that is preventing the trigger?

Any other recommendations for troubleshooting this issue would be highly appreciated. Thank you for your assistance.