This article applies to NoMachine servers v. 4 or later.

By default NoMachine server is configured to limit number of concurrent connections, virtual desktops and users who may run sessions on contemporary to 20. This means that even in case of a subscription with unlimited concurrent connections and/or virtual desktops, every attempt to start the 21st session will be blocked.

Administrator may edit the server configuration file and increase limits according to their needs.

Please refer to this article for more detailed instructions about how to customize these limits:

https://www.nomachine.com/AR08M00858

Note that depending on which limit is exceeded, users get a different message:

1) Reached the maximum number of concurrent virtual sessions on this server  -> when limit on virtual desktops is exceeded

2) Reached the maximum number of concurrent sessions on this server -> when limit on concurrent connections is exceeded

3)Virtual Session capacity: reached for user: <username>  -> when limit on how many concurrent virtual desktops a user can run is exceeded

4)Server capacity: reached for user: <username>  -> when limit on on how many concurrent connections a user can run is exceeded

Other references:

1) How to terminate NoMachine virtual desktops sessions automatically

https://www.nomachine.com/AR08M00854

2) Server administrator's guide for NoMachine 5, Managing sessions

https://www.nomachine.com/DT07M00090#7.2.

3) Server administrator's guide for NoMachine 4, Managing sessions

https://www.nomachine.com/DT01L00064#7.2.

4) Users' and sessions' limits for NX 3.5.0:

https://www.nomachine.com/AR09C00284