Plaxis 2D Tutorial 09

Sir I have Done Tutorial 09 - Stability of dam under rapid draw down by changing the dimensions of the base of core.

Actual base coordinates are (10,0) and (-10,0)

On a thought to know how the factor of safety changes by changing the core dimensions i have changed them to (15,0) and (-15,0).

But I can't get output. Intial phase (high reservoir) is not getting calculated.

I have attached the screenshot and data.success file of that error.

Please kindly look over my problem sir.