Blindness to visual cues can be cured. Pay attention to your audience as you speak. Read them. Are they looking at their watches? Are they scrolling on devices? Sorting their inbox? Packing up to leave?

They're not listening to you. Either something else is more important to them, or you've lost their interest. Their distraction may even be innocent. Unintentional. But don't continue. Choose to re-engage them, or let them go.