If the desktop or mobile app refuses to open or crashes immediately, start with the basics: clear the app cache. On Android go to Settings → Apps → Spotify → Clear Cache. On iOS, reinstall the app entirely — iOS doesn't expose cache controls directly. Make sure you're running the latest version; outdated builds often break after server-side updates.
This usually comes down to corrupted offline cache or a licensing mismatch. Try toggling Offline Mode off and back on, then restart the app. If specific tracks are greyed out, they've been pulled from the catalog in your region — nothing to fix there, the content is simply gone.
Failed login attempts are often caused by a mismatch between login method — for example, trying to sign in with email when the account was created via Facebook or Google. Use the 'Forgot Password' flow even if you remember the password; this resets the auth token and often clears the block. If you get an 'account temporarily locked' message, wait 30 minutes before retrying.
Poor streaming quality or constant buffering points to bandwidth issues on the client side. Lower the streaming quality in Settings → Audio Quality → Streaming. Also check if other apps are eating bandwidth in the background. Switching from Wi-Fi to mobile data (or vice versa) can help isolate where the bottleneck is.
Offline downloads vanish when you haven't connected to the internet for 30 days — the app requires periodic online verification. They also get wiped if you log out or reinstall. Re-download your playlists after logging back in and keep at least one online session per month to avoid losing them again.