Hello,
Sorry for later reply, you downloaded the past event from Livestream? Actually, as long as you enable the video detector, it will be added into the download queue. I am just testing on my PC and everything proves to work normally. The moment I open a video that has been broadcast for playing, the advanced sniffer immediately grab the video. You may refer to the screenshots as below:

And if you have tried several times and failed to work again, you are suggested to uninstall the program and re-install it on your PC. If finally have no luck, then could you please send some example urls to me so that I can figure it out? Thanks for your suggestion and feedback.