Hey, ya'll are right guys. Looks like the Restore jobs on the Secondary database is not restored successfully.
( Eventhough it shows that job run successfully )
The sql event log shows that the trn files are skipped while the trying to Restore. I am pretty positive that it has to do something with the transactional log sequence number.
The day when I did this log shipping setup there was a log backup job ( our original log backup from the maintenance plans ) still running parallel to our new log shipping transactional log backup . So as soon as I realized that there were two transactional log backups running side by side and interfering with each other's lsn's I disable/deleted the original log backup. But I guess I was too late.
Now, I am pretty positive that deleting all transactional log backups and setting up the log shipping from the beginning will solve this problem.
I will keep it posted...
thanks for all the help.