You may notice that different wording is used here and there in documentation and on the website. Here we aim to provide some clarification. What the licensing system really counts is the amount of active VPN tunnels. This means various scenarios are possible. For example, you can configure 1 user account on your OpenVPN Access Server and set it up so that with that same user name and password you can establish a VPN connection from multiple different devices at the same time. You could set up an account "andrew" and a password for it, and use that account on an iPad, a Windows computer, and two Macintosh computers, all at the same time. In such a situation if all those devices are connected at the same time you're using 4 connections on the license. If your server says it is licensed for 10, then that leaves 6 connections free.
It also works the other way around. You can have 500 user accounts on your Access Server but only license it for 100 connections, and if 25 of those 500 users are connected then you can still connect 75 VPN tunnels with any of the 500 accounts. So in other words, the licensing system does not look at how many user accounts you have, but how many VPN tunnel are connected at the same time. So if you have 500 user accounts but you anticipate that only about 90 of them will ever be online at the same time, then a license key for 100 is perfectly fine.
And if for example you have 10 VPN tunnel connections active on a server that is licensed for 10, then anyone trying to establish the 11th connection will be denied access and receive a message that the licensed amount has been exceeded. When one of the currently connected tunnels is stopped, then that opens up 1 license and the user can then log in.