lisence issue

I had no problem to use PSIM before. However, I was not able to use PSIM with my current account right now. 

It pops up "Connection to the license server is lost. Save your work and exit. If connection is not restored shortly, the application will shun down"

I am sure my internet connection is good. I am currently in China mainland. I tried with three different network: internet from mainland, VPN from Virginia Tech and hotspot roam from HK SIM card.