Thats because Nordeus, in their infinite wisdom has decided that it is not a good solution to have the manager actually ACCEPT a friendly before it can be played.
I have to call out Nordeus and call them ****ing retards for this decision. Seriously. Thousands of people have complained about this very issue and they refuse to do the correct action, which is program a way to accept the friendly, otherwise it is automatically declined.
Fix this ****ing issue Nordeus. Seriously! Do your ****ing jobs and actually listen to your customers and followers.