DirectSearch2 Function DataFit runs endless. But Searching with DirectSearch convergates!

Hi Experts,

Here is my File. I use the DirectSearch2 Library.

Searching the Minimum works fine. (800 sec on i7 PC)

But the Datafit runs endless.

I tried to make the fit with min SSE that works, but why does DataFit not succeed?

Thanks for answering.

Walter

GroundWater_Solution.mw