HI everybody,
I've published a public survey on my company's Portal and everything was working without any issue since a couple of weeks ago.
Then the survey was no more reachable due to the following error:

It seems to be a problem on the CloudFront server.
Any of you is experiencing the same issue?
Can you help me?
P.S. Due to security policy our Portal is reachable only through VPN connection
Many thanks,
Riccardo