When trying to connect to the ThinPrint License Server the authentication fails using PowerShell after user is prompted to enter credentials. However connecting to the ThinPrint License Management console using the same credentials works fine.
There are several reasons that can influence the authentication via PowerShell. One reason could be a wrong set up IIS authentication method for Anonymous Authentication in CCSRest. By default the ThinPrint License Server installer should set Anonymous Authentication to disabled, but for some reason this is not always the case.
Disable Anonymous Authentication in IIS for CCSRest (see images below).