DSLS licenses cannot be transferred from one computer to another. The license file provided is tied with server system’s MAC ID\\target ID .
In order to install the DSLS server on a different computer,a new license file will be required. 
First get target ID of new server then contact Dassault Systems reseller to request a new license file. 

The procedure to move licenses from one DSLS to another is also documented in this DS Knowledge Base article: https://kb.dsxclient.3ds.com/mashup-ui/page/resultqai?id=QA00000049464e