Syncing local files from desktop to Iphone 6s broken.

[ottoyouds]

I've gone through the help sections with no success, I'm trying to install local songs to my phone via my desktop PC. I am using an Iphone 6s and both devices are fully updated(today). It's worked in the past it's always hit and miss. At the moment it's a grey circle with a downwards arrow

Plan: Family Premium (I'm account controller)

Devices: Iphone 6s, Desktop PC windows 10

Constants: Been on same network, BlueTooth on

Things I have tried:
Turn fire wall on (Ticking both private and public for Spotify)
Plugged phone in and out of computer (Neither work)

[ottoyouds]

Update: Could the kb rate of the songs matter? Why would they cap something that has no effect on them?