First, double check your slide animation settings. Animations can be reset for a specific slide or all slides in your presentation. To access the slide animation window, click on the Animations tab located on the ribbon.

If the animation settings are too complicated to edit, you may want to try resetting your presentation from scratch. To do this, open the presentation and click on the Home tab. Under the Slides section, click on Reuse Slides. Select Reuse Existing Slides and click OK. On the next window, choose the presentation you want to reset and click Open.

If you only want to reset the animation of a specific slide, you can do so by opening the Animation Pane. To open the Animation Pane, click on the Animations tab and select Animation Pane. In the panel, select the animation that you want to reset and click on the trash can icon to remove it.