Why cant I raise my Purchase Order?

If when you come to raise a purchase order the Raise PO button is greyed out it will be because one of the follow problems

Issue 1
The Sales Order is on Hold, go to the 'Shipping/Payment' tab at the top and make sure this box isn't checked. If it is, uncheck the selection.

Issue 2

 

 

If the customer has been put on hold then this will stop you from raising the PO as well, check the financial tab in the customer record