This article describes the steps which are needed to be taken when a pop up with a message "Please activate your organization" will appear.
If the customer organization was not "Approved" when creating an organization, the new organization can't place orders. The customer will see the pop-up message when trying to purchase an offer: "Please activate your organization. Your organization needs to be approved before you can make purchases. Please ask your Account Manager to approve you and try again".
In order to allow placing orders, "Approve" the organization. In more detail please read the following article How to activate organization?