AEM Authoring - Version Restore preview option not working.

Hi People, 

Good Day!

I have been facing a issue with Preview as well as compare version option with page versioning in AEM 6.517  as well as 6.5.21.

I have checked in the CRx the node exists under the /tmp/versionhistory/ folder but no preview is getting generated. 

Any possible solution for this problem. 

Thank You.