Accounting Interface: Balance in Transaction Currency &1 (&2)

What causes this issue?

The balances in transaction currency must be zero for each logical
transaction when transferring to the FI/CO interface. A balance of "&v1&
" "&v2&" was determined for the logical transaction "&v3&".

System Response

The FI/CO interface does not process any transactions which have a
balance in transaction currency other than zero.

How to fix this error?

This is a system error in the calling application.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.