Access to this particular resource is limited to a certain number of simultaneous users, so if you receive this message it is because this limit has been reached at that time.
Anyone who encounters this problem should simply exit the site try accessing again at a later time.
For those using the resource, we ask that once you've finished your session on Naxos you either
- close the browser window
or - click on the red Log-Out button at the top of the screen