CloudFront has quotas[0] and they likely just hit those quota limits. To request higher quotas requires a service ticket. If they have access logs enabled in CloudFront they could see what the exact error was.

And since it seems this is hosted by Atlassian, this would be up to Atlassian.

[0] https://docs.aws.amazon.com/AmazonCloudFront/latest/Develope...