I am facing following error while assigning the material property to the lambda. It will be really helpful if PLAXIS team can sort out for me.
Dear Rituraj,
In your code, I see that you are defining a new material to which you assign a variable called mat5.Then two lines below you rename mat4, which is not mat5 which you specified as a Modified Cam-Clay model.
Finally, you try to edit mat4's parameter lambda to a value and that fails.
Maybe mat4 is not a Modified Cam-Clay model, and you made a typo?
I always check the PLAXIS command line to understand what the error is. Maybe there you could spot the difference.