Why am I getting incompatibility report and can't open an Illustrator file in Animate?

I found the best way to get items from illustrator to adobe animate is to just literally copy the files inside illustrator and then paste it right into enemy it will paste with all the layers and work just fine. 

Some Illustrator effects like feathers, advanced gradients, complex text/stroke styles and so on aren't fully compatible with Animate, that's what the warning is about. See this page for more information. Clicking the incompatibility report generally lists the problematic items in the AI file, some of them can be corrected by using the recommended settings suggested in the Import options area of the AI Import dialog box.

If this fails you can still ignore the warnings and import the file to the stage anyway to see what elements are causing problems and fix them in Illustrator either by removing effects, convert text and stroke styles to outlines or in the worst of cases import them as bitmap.

Note: You don't need to re-save the Ai file, you can just copy-paste the objects into Animate after you edit them.