@PepSV. Thanks for posting your question. The plugin does not have in any code that limits its usage to admin users. Let me know what you did, and we can figure out what is going on.
Also, please explain what is happening that makes you think that the plugin doesn’t work in articles created by non-admin users. However, as long as you can created an article you can type the text for the plugin to work. One of the issues you may face may actually be a filtering issue.