optimization back test reject profit cases

Seksan Sangsawad
121
Seksan Sangsawad  
I've tested EA with optimization back test (36 cases), I got just 1 profit case. So, I uncheck "skip useless result" for getting all result. I got 1 profit case, 1 loss case, and 34 zero profit cases. I decide to choose 1 of zero profit cases for doing normal back test, the result for this case I got a lot of profit. I wonder why mt4 reject this case. Is there anyone could explain to me????