There is no way to answer this question without details of the posting.  It is either a data entry error, posting control setup error, or could possibly be a bug.  No way to know from just an error message.

Hi

There is no bug to my experience. I think you have a missing posting control. Or allowed voucher variance setting in company set up

Hi Manish,

I'm not sure if your issue has been already resolved or not. But the reason for this issue is Rounding off of the parallel currency. If you check on posting information your parallel currency balance may have a negative or positive value. To resolve this issue you need to modify the Parallel Currency Debit or Credit Amount to make sure Parallel currency balance is zero. Then you will able to post the issue.

Thanks and Regards,

Akila