If you're seeing watermarks on some machines but not on others, there's usually a simple explanation: those machines cannot connect to the license server. The first thing you should do is check the RLM diagnostics on the license server. In particular, look for the solidangle Statistics, which will show you whether or not licenses are being denied. Here's an example from a real-life rlmdiag.txt file:
Now that you see that there are no license denials, you can move on to testing the connections from the client machines to the license server.
To get the RLM diagnostics and the solidangle Statistics, you can use the RLM Web Admin: open a web browser and go to localhost:5054 (if you're sitting at the license server computer) or <lic-server-name-or-ip>:5054 if you're sitting at another machine.
You can also use the rlmutil command line: