Bal. carryfrwd for company code &1 is not possible (migration to New G/L)

What causes this issue?

You have started balance carryforward in classic General Ledger
Accounting for company code &V1&. However, this company code is assigned
to a migration plan for General Ledger Accounting (FI-GL) with migration
date &V2& in fiscal year &V3&; therefore it is not possible to execute
the balance carryforward program for the fiscal year &V3& or any fiscal
years before this.

System Response

Processing is terminated.

How to fix this error?

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

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.