Cannot assign free apps to an iPad from Blueprint

I have added various Free apps to my Blueprint in Configurator 2.2.

When I try to apply the Blueprint all I get is the same error for each app whilst the Blueprint is trying to add the apps to the iPad:

"Cannot assign a copy of " app name " to "ipad"

"There are no copies left. Go to the VPP website to purchase more copies and try again"

Now I can assure you these are free apps I'm adding and not the paid ones, so I cannot understand why it is asking this.

Any help welcome!

Kind Regards