Robot stopped and forced to close program during the run

I was trying to run the attached script but every time robot is stopped in the middle and the whole uipath program is forced to shut down and close the application. (The time and the step where robot is stopped is different in every run, which means it is not a particular step problem…) May I know the reason behind and how I can avoid this problem? Thanks a lot!

test_1.xaml (1.0 MB)