If I am not wrong, your existing leave policy has ended. Any remaining leave balance from this leave policy will be carried forward to the new leave policy. Hence, the applicant cannot apply/cancel any of the leave application that was done during the already-ended-leave-policy.
But if I am wrong, please put in some context so that anyone in the forum will not have to play the guessing game. A screenshot alone isn’t enough.
I already submitted the leave allocation for entire month in this Year. After that I apply leave for this month it shows error.