Ret.acct.period must be after earliest ret.acct.date (&) of payroll per.

What causes this issue?

The retroactive accounting date may not fall ahead of the earliest
retroactive accounting period set for the payroll area.

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?

You can set the retroactive accounting date to the beginning of the
earliest retroactive accounting period.
If it should be necessary to recalculate a date which falls ahead of the
earliest retroactive accounting period, reset the first day of this
period.

Error message extract from SAP system. Copyright SAP SE.