I know that its over a month since you posted but as I have just experienced this and found out how to get it sorted I thought I would share. When you click the Apply New License button and it opens up a file browser if you create a new folder then transfer the .btskey file to the newly created folder it should show up. For whatever reason if you have the file in the sync folder it doesn't show up but if you create a folder within sync using this method then it works fine.