You`ve been working on a CloudFront whole site CDN. After configuring the whole site CDN with a custom CNAME and supported HTTPS custom domain (i.e., https://domain.com), you open domain.com and receive the HTTP 502 status code (Bad Gateway). 

Answer options:

A.The SSL/TLS certificate on the Origin has expired or missing a third-party signer. To resolve this purchase, add a new SSL certificate.
B.HTTPS isn`t configured on the CloudFront distribution, but it is configured on the CloudFront origin.
C.The user does not have enough permissions to login to the website.
D.The validation Lambda has failed to validate the request.

Answer – A
Options B, C, and D are INCORRECT because these options do not result in the 502 status code (Bad Gateway).
For more information on CloudFront CDN, please see the below links
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/http-502-bad-gateway.html
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/AmazonCloudFront_DevGuide.pdf
http://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html
https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/http-502-bad-gateway.html#ssl-certificate-expired