Constant Content

In the past, I have submitted articles I have written and published elsewhere on the web on CC for usage only, and had these articles approved. Today, I attempted to submit two articles that I have published elsewhere, again for usage on the CC site, and they were rejected for editors reason "we accept original content only." Have the rules changed? I had an article approved just days ago that had been submitted on other sites, now all of a sudden it isn't accepted. Am I missing something? Thanks for any input:)