Floating token licenses are based on the client-server paradigm; the token server issues tokens to client machines to run optimization jobs locally on the client machine.
Each client machine must have a client license file gurobi.lic that specifies where to find the Gurobi token server. This file typically contains a single line of text, containing the key TOKENSERVER set to either the Fully-Qualified Domain Name or the IP address of the token server.
This file needs to be located in a place where Gurobi can find it; please refer to Where do I place the Gurobi license file (gurobi.lic)? for more information.