Customer packages should not be assigned to SAP switches

What causes this issue?

Packages in the customer namespace should not be assigned in the SAP
namespace using modification switches.

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?

Create a new switch in the customer namespace and assign the package
&V1& to this switch. Afterwards, assign this switch to all the business
functions to which the switch &V2& is assigned.

Error message extract from SAP system. Copyright SAP SE.