Syncing Local Files to iPhone

[Robbie95]

Plan

Premium (family)

Country

United States

Device

iPhone 11 Pro

Operating System

iOS

My Question or Issue

So I am having trouble syncing my downloaded songs from my desktop to my mobile device. I have the folder connected to my Spotify and have the downloaded songs I want in a new playlist on my desktop and they all play fine on Spotify and on the default music app for Windows. When I try to add them onto my mobile device it shows most of them but leaves out about 30 of them. And then even though it shows the rest and shows that I have them downloaded on my mobile device it only lets me play about 20 out of 260 songs. They are not greyed out and have the green downloaded arrow next to them. I am on the same internet and account and have even tried using my phones hotspot for internet on my desktop to ensure they’re on the same connection.

Any help would be useful!

I also have windows defender allowed for my Spotify which I have never had problems with before. 

[Robbie95]

I have also tried turning off windows defender in my firewall settings and that did not help at all either.