Hi, Thanks for both of your replies.
I have fixed the issue by doing couple of more log backups then I shrank and it worked.
arnipetursson, However, I am curious to learn what exactly you mean by saying this "It is likely not shrinking because the active part of the log is at the end."
I know that each records gets created in a VLF files.
Also, by applying the manual check point, are we forcing the active portion of the log to apply to mdf, and therefore it will become inactive log as well......is that the purpose of applying manual checkpoint? Please advise.