Well, I just synced my local music again with my iPhone and works great, the way I did it was like described in my previous answer, that means it still works, so it's only you with the problem. My suggestion would be to check your proxy setting, if you have them enabled, disable them, that worked for me this time I tried to sync from work (which I had to disable proxy and share my iphone internet to sync, because the internet from work is restricted in some ways)
For me, I added all the songs I wanted from my "Local Files" playlist on my MacBook on Spotify to their own playlist and made it available offline to my computer. Then I found the playlist on my phone but it wouldn't download offline to my phone. After this realization, I was able to find the directions screen that told me: 1. Connect this iPhone to the same WiFi as the computer. 2. Launch Spotify on the computer where the song is stored. 3. Mark the playlist containing this song for Offline Sync on your computer or on this iPhone. 4. Watch as your song magically appears on your iPhone.
After closely following these steps it still did not work. I even tried restarting both the phone and the computer and changing WiFi's without success. For me, what caused the songs to download to my phone was turning on Personal Hotspot on my phone from Settings and connecting my computer's WiFi to that hotspot. As soon as I opened the app, it downloaded instantly.
I was having the same problem as the OP and this is what finally worked for me as 0pTicaL laid out. I have WIndows 10 and Android. I went into Windows Firewall, opened up advanced settings, went to inbound rules, and found two spotify.exe public rules that were set to be blocked, I set them to be allowed and my phone immediately started to download the songs. What most likely is happening is that there was a recent update to either windows or spotify that doesn't allow spotify from your phone to tell your computer to allow it to download from the computer, even though it knows which files you have in the playlist. This is actually a true security issue, but you could always set the blocks back up after you finish downloading.
For some reason spotify.exe adds a new exception to Windows Firewall every time it updates itself, generating a long list of spotify.exe entries in the firewall list. What I do is shutdown Spotify, delete all the entries under Windows Firewall > Advanced Settings > Inbound Rules, and allow spotify.exe again. I have tested that you only need to allow Private connections for Spotify to work, allowing Public connections is not necessary.
It might be that some of the people experiencing problems with the local syncing have disabled dependencies in the sytem configuration that prevents spotify from relate wireless data (windows 7,8,8,1).
To see if this is the case:
1.WINDOWS KEY + R
2.Type in "msconfig"
- Two options now
1. Lazy option - Go to 'General' check 'Normal Startup' box (all device drivers and services) - Apply and restart.
2. Specific option - Go to 'Services' (If you previously have disable various services, you can try simply 'Enable all' and restart. If you want to find the specific process, I suggest you look for a wireless related service that might be disabled and enable it.
Make sure all your firewall settings are correct as stated in this post, apply these configurations changes, restart the computer and then try syncing.
The solution for me was that there was a frozen spotify running on one of my computers. After killing it off and rebooting that computer, I was able to sync on my mobile device.
So it wasn't the limit of number of songs that can be synched, not the limit of 3 devices that can be synched - it was a dodgy spotify app running mad on one of my Mac's on my network. All I had to do was kill it and reboot.