My canonical is different than my url

Hello,

I have a problem with the canonical on my website.

I use the plugin Q&A Wpmudev and the urls of the plugin are : http://www.mywebsite.net/communaute/comment-faire-face-a-une-transpiration-excessive-du-visage

But When I activate “Enforce a trailing slash on all category and tag URL’s”. I activated this option for my categories and pages.

The canonical is : http://www.mywebsite.net/communaute/comment-faire-face-a-une-transpiration-excessive-du-visage/

The url is different than canonical :

My url : http://www.mywebsite.net/communaute/comment-faire-face-a-une-transpiration-excessive-du-visage
My canonical : http://www.mywebsite.net/communaute/comment-faire-face-a-une-transpiration-excessive-du-visage/

It’s a big problem for me, how can I resolve that ?

http://wordpress.org/extend/plugins/wordpress-seo/