Previous period and last period of previous year have different values

What causes this issue?

You have maintained different accounting data for the previous period
and for the last period of the previous year. However, these periods
are identical since the current period is period 01 of the current
fiscal year.

System Response

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

How to fix this error?

Check your entries and correct them.

Error message extract from SAP system. Copyright SAP SE.