I have standalone PSIM+simcoder license and was running OK, but today it shows error "The C script engine didn't load" for all my PSIM simulation ?

Hi, M.

How did you get this error message? Please describe the steps which lead to this error message.

Did you run simulation of a PSIM example? Which example?

Did you have a DLL block in your PSIM schematic? Please upload the schematic and the DLL file. 

If you do not want to publish those files, please go to the support portal:
Create a support request

Please refer to the answer in this link to enable the SimCoder feature in your license:
License setup issue