Thanks for the response. Actually A TAC was created for this issue after this post . TAC engineer did the same thing but slighlty different.
He did "Disable CDS and HDS" and enabled it on the same page. Once after that everything started replicating from Pub to Sub.
Secondly when we were checking the status here, for the config data store, the Synchronise Data operation button was grayed out. This is just a finding.
Now everything works normal
Thanks once again anand for the reponse .