3023598 - Transfer Button is Greyed Out in Sales Order

When trying to transfer a Sales Order to the external system, you notice that the "Transfer" button is greyed out.

SAP Cloud for Customer

1. Go to Sales workcenter, Sales Order view.
2. Open Sales Order XYZ, click on the "Actions" button. 
3. See that the "Transfer" button is greyed out.  

The customer that is being used in the Sales Order is a Prospect.

Prospects are blocked for external follow-up documents. Only Accounts are allowed.

Sales Order; Account; Prospect; Transfer; Greyed Out; , KBA , LOD-LE-CQP-CO , Lean Sales Orders , LOD-CRM-ACC , Account , How To