Also set the indicator for 'Calculation after end of useful life.'

What causes this issue?

You chose the setting 'Depreciate below net book value zero' and/or the
setting for 'Effective life after planned end.' Both settings are only
allowed if the indicator 'Depreciate after planned life end' is set.

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?

Correct your entry, or set the 'Depreciate after planned life end'
indicator.

Error message extract from SAP system. Copyright SAP SE.