Cognizant Engineer Trainee interview questions

The overall interview process was pretty smooth and I also performed well. And after the document verification round I got a rejection mail instead of getting an offer. Till date I don't know why I got that rejection mail that too after the doc verification round.

First step is aptitiude. Following qualification, there is a long interview where you are asked some basic IT domain questions from Database, Cloud, OOPs, mainly. Passed it easily but the response came almost after a month