Everytime the position gets shifted to the same previous point even after changing it using toucup option

HI all,

I am simulating a machine tending operation using a robot as shown in the screenshot below, it gets stuck in one particular process saying that the particular position is out of reach (note: it runs fine for the 1st time) and then i change the point to same position as the 1st time when it executed successfully but still the point gets shifted to the same out of reach position.
1st time the process is executed but the second time it shows this error.

Can someone please tell me where i am making the mistake ?