As far as I am aware, articles or contents of members have to be original for getting accepted. If we just submit an already published (print or online) article (even if we are the authors) then, it is bound to be rejected.
Further on, ISC has a copied article checker (you can see this if you click on dashboard in the drop down menu just below your name after you login). This is to check if one of our original articles has been copied or found in other site.
So, what you can do is check the topic on which you have written, find a new point of focus or issue that can be expanded,add new material or key points and submit a fresh article that does not have the same old content. Then you would have a better chance of acceptance.