I think it is reasonable to create a new Support Case for this issue
Hi @Nagah.khaled,
This error could be due to a number of reasons. Those reasons can be missing posting proposal, allowed voucher variance setting in company set up, data entry error or due to a bug. As a result, there can be the Rounding off of the parallel currency. You can find these rounding off differences in the Posting information. In the posting information, the balance in parellel currency may have a negative or positive balance. You need to make this parellel currency balance equal to zero by debiting or crediting. This is only a one way of how the issue can be resolved.
However, if the issue is not due to a one of above reasons, as @Georgios Schmidt suggested, you need to raise a case to IFS Support for further investigation.
Kind regards,
Shanuka.