Restart your device first. If that doesn't help, check for available updates in the App Store or download the latest version from Apple's website for desktop. Clear the app cache by going to Settings > General > iPhone Storage, find the application, and offload it temporarily. Reinstall if the crashes persist. On Windows, run the repair tool from Control Panel > Programs and Features.
Verify your internet connection is stable. Open the app, go to Account settings, and check if you're signed in with the correct Apple ID that made the purchase. Sometimes downloads get stuck — tap the cloud icon next to the item to restart the process. On desktop, go to Account > Check for Available Downloads. If items still won't download, sign out completely, restart the device, then sign back in.
Ensure iCloud Music Library or Sync Library is enabled on all devices. Go to Settings > Music and toggle the sync option. Both devices need the same Apple ID signed in. Check if your iCloud storage isn't full — that blocks synchronization. Poor internet connection also prevents syncing, so switch to a reliable Wi-Fi network.
Streaming quality adjusts based on connection speed. Switch from cellular to Wi-Fi if possible. Close background apps consuming bandwidth. In Settings > Music, you can change streaming quality to use less data. Reset network settings if buffering happens constantly: Settings > General > Reset > Reset Network Settings. Router placement affects signal strength — move closer or restart your router.