BFFF0011 error when opening session to control temperature chamber

I have an strange BFFF011 error when trying to open a session to Vötsch Temperature chamber . When running the code , you can see in the screenshot, sometimes viOpen return that error:

Ok, maybe the device doesn't respond

But when I I hit press the break button after the failure  and execute the functions manually in the interactive execution window, it allways works:

Any ideas whats going on there ?