Lito Yap
Ansys Employee

@Youngin Kim, 

from your message, 

However, I have successfully ran the FDTD simulations which have more than three sources (or even up to 16 sources) in the institutions where I worked in the past. I do not know why this does not works in my current working place.

We are unable to reproduce the issue on our Linux machines. We also do not know what is happening on your system/installation. 

This is probably an issue with your current system. Did your IT check for the required libraries as per this Knowledge Base (KB) > Installing on a shared filesystem on Linux – Ansys Optics ? These libraries should be installed or accessible by all nodes that will be running your simulation. 

Based on your screenshot, you are using an older version, 2022 R1.1 -- ask IT to install the latest release, Lumerical 2023 R1.3, available in the Ansys Optics downloads page. We use the latest versions that are available on our website for our tests/reproduction of the reported issues.