&1 cannot be used; enable the new database first

What causes this issue?

You are trying to use a function that is based on the new database for
multiple data source.

System Response

The system cancels the user action.

How to fix this error?

To continue with you action, you must first activate the new database in
Customizing for <LS>Sales and Distribution</>, under <LS>Billing ->
Billing Documents -> Country-specific Features -> Country-Specific
Features for China -> Multiple Data Source -> Activate New Database</>.

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.