Depreciation key &1 in ch. of depreciation &2 not set to active

What causes this issue?

Depreciation key &V1& in chart of depreciation &V2& could not be set to
active due to existing errors.

System Response

The depreciation key is saved with 'not active' status.

How to fix this error?

Check the depreciation key in light of the error messages issued.

Procedure for System Administrators

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.