If you upload content from multiple sources, or reupload/repurpose someone else’s existing content (ie “reuse content”) then you won’t be eligible for YPP. Check out the FAQs and best practices here: https://yt.be/help/reused-content … and you can always reapply in 30 days.
I share my clips online for free, so people can use them as needed. I do it for exchange as I also download others' free clips. Due to the YouTube content match tool, I have stopped free sharing, because I am not the fist person who uses my own images, other people are.