Please check if your license includes a server. For example, if you have a Tibco Spotfire Desktop license, then, this does not have the Server license.
In order to install this license, you will need to remove your previously installed Analyst, which works with a Server, and then download and install the desktop version.
If your license is for a Spotfire Analyst Personal Subscription, the credentials you need to use are the same ones for the www.cambdridgesoft.com website. You must have activated the license first using the link included in your fulfillment email.