Billing classes are inconsistent

What causes this issue?

Billing class &v1& of price class &v2& and price level &v3& is not the
same as the billing class &v4& of the installation.

System Response

Billing is canceled.

How to fix this error?

Ensure that the billing classes of the price and the installation are
the same. If you want to use and bill rental prices across billing
classes, you can deactivate the check as described in note 815463.

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.