I HAD CONFIGURED LOG SHIPPING BETWEEN TWO SERVERS.
LAST NIGHT, THE LOG SHIPPING CHAIN BRAKED DUE TO LSN MISMATCH.
I FOUND THE ERROR IN SQL SERVER LEVEL LOG., AS IT SHOWS LOG BACK UP HAS BEEN PERFORMED TWICE AT THE SAME TIME AND IT SHOWS TWO LOG BACKUP FILES HAVE BEEN CREATED IN SHARED FOLDER THAT TOO MESSED UP LSN.
AND THEN I CHECKED FOR THE LOG BACKUP HISTORY IN MSDB. BUT, I COULD'NT FIND THE CORRECT LOG FILE TO GET RESTORED.
THE MSDB LOG BACKUP HISTORY SHOWS THAT THE LSN OF BACKUP IS MESSED UP WITH BEFORE BACKUP.