Lito Yap
Ansys Employee

Is the Ansys LM up and running and showing the available license for checkout? 

https://optics.ansys.com/hc/en-us/articles/4405401057811-Ansys-license-manager-installation-guide-for-Windows#toc_5 

If the Ansys LM is up and running and the licenses are shown. and you are running the Ansys license manager on the same machine as where you are running Lumerical, enter "localhost" in the Server field as shown in the image below.