This is a common issue that can easily be fixed. Simply go into the admin of your site and navigate to the ‘Settings’ section of the admin. Under ‘Settings’ there should be a ‘Permalinks’ section. Under that page simply click on ‘Save Changes’ again to re-save your permalinks. By default the Testimonial Rotator plugin creates an archive list of your testimonials at “/testimonials”. You can change the slug to whatever you want by following this tutorial.