I am assuming this is a development server..
The Development Server from TechNet is limited to 1 Connection for Go/WebDirect Clients.
Thank you for your post.
Open Admin Console for the server, and check Activity to see if any clients are connected to "AOK_Development.fmp12". If there is a client, then ask them to close.
In my experience this message does not represent a licensing problem. What it really says is that the server has reached its processing limit I've only seen this message once. I quit the client and relaunched. The problem failed to reappear. The Maximum Users exceeded message is very specific and will cause the client application to quit. This is a different issue.