HTML Validation Error

hi guys
I have finished building Moshify but I get 2 html validation errors.
anyone knows how to fix them and what they are?
density for image ipad.webp is identical to density for image ipad@2x.webp
element span not allowed as child of element ul in the context.(suppressing further errors from this subtree)

and now that I have build my website with parcel and viewed it in this portal http://localhost:1234/
my ipad.webp is missing and is not shown.
I am guessing it relates to that image density issue