Testimonial page stops working when /category/ taken out

I’m working on a site where I’d like the url to not include /category/. The Yoast SEO plugin has a checkbox for this and I’ve tried the WP No Category Base plugin as well. Both do what I want, but when they’re active, the Testimonials page breaks and says “nothing found”. My other CPT pages come up just fine.

Any thoughts on how to handle this would be appreciated!
Thansk

http://wordpress.org/plugins/testimonials-widget/