Labview to control two ESP301 controllers

Hello All,

I have written labview code to control two ESP301 controllers simultaneously via USB using flat sequence structure. But when I run the VI, the initialize block in the first flat sequence frame generates an error :-1073807339 labVIEW error whereas the second frame runs without any error and could establish communication when the logic is the same. 

NOTE: both the controllers are connected via USB separately and both the controllers have the same controller address 1.