Some browsers are blocking pop-up windows. Same browsers will also block URL Opener from full functionality. You need to allow opening pop-ups from website link-brain.com. Firefox should be fine. You’ll find info screenshot for Chrome below. And Opera is almost the same as Chrome.
And don’t worry, there are no annoying pop-ups on this website. I hate them as much as do you. By allowing pop-ups, you’ll only unblock the core functionality of this tool.
Chrome