Full repository analysis with Codeguru Reviewer associated with S3 Repository keeps failing due to "problem with source code access permissions".

I have successfully associated an S3 repository with Codeguru reviewer and created Full Repository Analysis with the AWS node.js SDK. The code review failed multiple times with the following error message:
"CodeGuru Reviewer was unable to retrieve information necessary to process your request. This usually indicates a problem with source code access permissions. If the error persists contact AWS Support."

To fix this, I added the CodeguruReviewerFullAccess and S3 Full Access policies to the user group from which the above actions were performed. After this the code reviews have been in a pending state for over 3 days with the message:
"CodeGuru Reviewer failed with a transient exception while reviewing the source code. Your request will be retried."

I am unable to diagnose the source of error.