There are no limits on how many outgoing NoMachine connections you start. What counts is the number of incoming connections. Let’s look at an example. You have installed the free version on the computer you want to connect from and you’ve also installed the free version on the computer you want to access (the “server”). The number of connections you can start is unlimited. On the server side, one incoming connection will be possible. If you install Enterprise Desktop on the server machine, unlimited incoming connections will be possible.
Please also take a look at the following article:
What is the difference between NoMachine Free Edition and NoMachine Enterprise Desktop?
https://www.nomachine.com/AR07L00808