Spotify for iPhone won't play songs which are in my iTunes library

[miljasmjs2001]

There are a few songs that I have in a playlist on Spotify that refuse to play on my iPhone 7. They are not greyed out, but when I tap on the song, the track appears at the bottom of the screen (as if about to play) for a split second before disappearing and nothing happens. These songs play perfectly fine on Spotify on my laptop, and I am wondering what makes this different to them being able to play on my phone? My iTunes library is exactly the same on my laptop and phone, so not sure why this is different. I never purposely imported the local tracks onto spotify and, considering that the Spotify library has the songs I am after, I would like to know how to stop it from trying to play an unplayable local track and just stream the file from its own database!!

Thanks,

Millie