Two computers show up as one

I have two computers with different computer names (Windows Embedded 2009), both with Xibo 1.71 installed. Xibo works fine on both.
However, the Xibo website only recognises one computer at the same time. Whenever I enter the key, the admin page is showing the latest computer instead of the previous one (but with the same computer name). Never a second one is added. In the Display page, the MAC address of the latest to connect is shown, so the computers are being recognised as distinct. However, the IP address is that of the router. The Xibo website is in the public domain.
Both computers do show the content, but the aim was to distinguish content of the two systems. Does anyone have an idea about this? Is there a way to configure Xibo that it only looks at the MAC address instead of IP?

This is covered in the FAQ:

Cheers! Works fine now.