Some Local Files will not transfer to my iPhone!

[Ellie720]

I have been trying to find answers for this all day and I tried multiple different suggestions but nothing seems to work. 

I've been trying to sync some Taylor Swift songs (since her music isn't on spotify) to my local files. The majority of the songs synced and work perfectly on my desktop and mobile app, but a few songs will not sync! Specifically:

Bad Blood ft Kendrick Lamar,

The Last Time ft Gary Lightbody, &

Everything Has Changed ft Ed Sheeran

all the other songs transfered without issue, so I am trying to find the problem. These are all purchased from iTunes (so .m4a files) and there is no similarities beside that these are the only songs feturing other artist. Is it possiable that the featuring of another artist is what is causing the problem? And/or has anyone else expirenced this problem? Please help me! 

Thank : ) 

iPhone 6s 10.2

Macbook Pro 10.12.1

Here is a screenshot of my local files playlist so that you can see what i mean by "grayed out", notice that the problem songs are gray, not white)