iphone not syncing with desktop

[eraserheadbaby_]

Plan

Premium (family)

Country

Australia

Device

iPhone SE

Operating System

iOS 15.3.1

My Question or Issue

I have the Spotify on my iPhone as well as the desktop app on my macbook however recently (the past few months) the devices have not been able to sync together. When using Spotify to play a song on my laptop my phone will not recognise that Spotify is currently being used and instead it is able to play another song simultaneously (and vice versa, any songs played on my phone are not recognised on my desktop). I also am unable to sync local files to my phone anymore, at most they will appear greyed out and unplayable but they cannot be downloaded even when I have them in a downloaded playlist. On both my phone and laptop the devices section does not display the other device. The only thing that seems to sync up is any changes I make to my playlists, but I assume this is because my account stores that data separately from any devices. 

This issue persists on both the desktop app and web player, as well as when I try connecting to different wifi connections or my mobile data. I have tried uninstalling the apps, signing out of everything, restarting my phone and laptop and turning on offline mode for an extended period but nothing seems to solve the issue. 

[Kiril]

Hey there @eraserheadbaby_,

Thanks for posting in the Community!

I get that you're having troubles syncing up local files with your Apple devices over your local network. I got to admit that syncing to iOS is a bit of complex matter, due to the overall closed nature of the OS. But I will try help out here with some more info on the topic. First off, have you recently changed routers? Or maybe done a firmware update for your old router? I'm asking this because in order to be able to sync local files between Apple devices, your router device needs to support the Apple Bonjour protocol. See if you can find out if this is the case for your device, and if the protocol is not supported, then maybe try a different router which has this to see if things will work as expected. 
 

Hope you find this useful. Keep us posted if you have any other questions.