Why is the Create Order Confirmation button grayed out? Why can't I confirm an order?

Error message:[Customer] does not accept order confirmations for material orders.

The Buyer has disabled the default transaction rule Allow Supplier to send order confirmations for material orders for this supplier or for the supplier group.

There could be several causes for why you cannot create an order confirmation; please hover over the greyed-out Create Order Confirmation button to view the reasoning,

One of the reasons can be that your buyer has disabled the default transaction rule Allow Supplier to send order confirmations for material orders.

See your customer's transaction rules to further identify the exact reason the Create Order Confirmation button is greyed out.

Purchasing > Purchase Orders > Order Confirmation
SAP Business Network for Procurement & Supply Chain > SAP Ariba Supply Chain Collaboration
SAP Business Network for Procurement & Supply Chain > Transaction Documents > Order Confirmation