Hi Nagarajan,
did you check the document in the customer check out itself? Are they marked as transferred?
And did you check if the documents are already in B1? If all documents were already transferred the synchronize log will have the status green (without error) as shown in the screenshot.
More information could be find in the partner edge
https://partneredge.sap.com/en/products/scc/about.html
Best regards
Stephan