Problem with casting simulation
 

Hallo, my name is Mattia, I'm italian and I'm in germany for write my master thesis. I using Star-CCM+ with the module Star-CAST in order to simulate a bridgman solidification.
My problem is that the simulation had work only one time, now if I take the same original file and I change the temperature of the heaters and melt, the program crash after more than 2000 seconds of simulation, with overflow problem (in the residual graph, the solidification line go to infinite).
The funny fact is that if now I take the original file with original temperature, i.e. the file that works the first time, now I have the same error and the file doesn't work! Why?

Thank you