Item &1: Transaction &2 is unavailable due to its status

What causes this issue?

Only transactions in status <ZK>Contract (without settlement)</>,
<ZK>Contract Settlement</>, <ZK>Rollover (without settlement)</>, or
<ZK>Rollover Settlement</> can be assigned to a sales order. However,
the status of the current transaction you want to assign is not in any
of the four statuses.

System Response

The system does not allow the assignment.

How to fix this error?

Change the status of the transaction, or select another transaction for
the sales order.

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.