Access Documents hosted behind the VPN via google viewer

We have a use-case. Our website is hosted on AWS and have rules at cloud front that states requests with specific IP range should be pass through CDN and documents will serve.

Now, there are certain documents that user view under google docs viewer say, https://docs.google.com/viewer?url=https://{{siteUrl}}/{{documentPath}} . As documents are hosted on same site which is behind the VPN, user not able to view the documents.

Any solution on how we can enable the view of documents, that will be requested by docs.google.com or how how we can allow docs.google.com in aws cloudfront/alb.

Thanks