Shared_ptr is not getting reset

When I am trying to reset a Shared_ptr type thread then the program enters into undefined state and hangs.

Once I execute the statement as shown in the screenshot below, nothing happens and the program hangs.

std::shared_ptr<WebApiDataWorkingThread> webApiPDatarocessingThread;

int Stop()
    {
        webApiPDatarocessingThread.reset();
        return UserFilter::Stop();
    }