Which ebook DRM does ebook ultimate converter support? I have ebooks purchased from both google play and kobo?

Hi!
Try to remove the drm from a kobo book with imElifin Unlimited and gets the answer that the program can't remove remove drm from Kobo Plus-books. But this isn't a Kobo plus-book, just an ordinary Kobo book. What is wrong and what can I do?
Best
Magnus