Error: Floating point error: invalid number
 

I recently use Fluent to simulation the process of injecting methane into a cylinder. The methane nozzle is very thin(0.5mm) and the pressure is very high (8Mpa).
After iterate for 119 time the error is here.

Error: Floating point error: invalid number
Error Object: ()

Do you have any suggestion?
Thank you in advance.