Most Apple Watches have limited storage; Spotify Support recommends at least 1GB of free space for a smooth experience. Why Your Spotify Download Failed (and How to Fix It) 1. The "Force Wi-Fi" Trick (Most Effective)
Many users find that downloads fail because their playlists are too large.
Disable Bluetooth on your iPhone and ensure your Apple Watch is connected directly to a Wi-Fi network . This forces the watch to use its own Wi-Fi chip, which is significantly faster for data transfers. 2. The 50-Song Playlist Limit
The most common reason for a failed download is that the Apple Watch tries to sync via from your phone, which is extremely slow and prone to timing out.