Yes, and that combination is the clearest signal you will get. Login and playback are two separate transactions. The first checks credentials against the portal; the second asks for a stream slot. An expired line, or a plan whose simultaneous-connection allowance is already spent, passes the first and fails the second. So a full channel list on screen with nothing playing is not a broken app. Walk the house before you walk the settings: a phone left on a channel in a pocket, a second TV on standby with the player still resident, a tablet in a child's room. Closing one of those restores playback instantly and explains why yesterday worked.

1. 1List loads, nothing plays: session refused, not login failed
2. 2Login rejected outright: credentials, portal address or port
3. 3Both fail on cellular too: the fault is not the Fire TV Stick

Xtream Codes logins fail in three quiet ways. The host is entered with a scheme the panel does not answer on, http where https is required or the reverse. The port is dropped, so the app tries a default that nothing listens on. Or an invisible trailing space rides along from a copy and paste out of an email, which the on-screen keyboard will not show you. Retype the details by hand once rather than pasting them, and use the phone app to confirm the same details work elsewhere. If the identical string plays on a phone over cellular, the credentials are correct and the fault has moved onto the stick.

1. 1Wrong scheme: http against an https-only portal
2. 2Missing port: the app falls back to one nothing answers
3. 3Trailing space from a paste: invisible on a TV keyboard

Because the player caches the playlist and will happily serve you yesterday's copy. When a service adds groups or moves them, the app keeps showing the list it fetched last, and if that fetch was interrupted you get categories with nothing inside them. Force a playlist reload from the app's own account or playlist screen rather than clearing app data, which would also delete your credentials. If a forced reload still returns an empty list, the failure is at the fetch, so check that the line is active and that a connection slot is free, since some panels will not serve the playlist at all once the allowance is spent.

Reinstalling helps in one specific case: an install that was interrupted partway through, or a build that regressed after an update. It does nothing for expired lines, spent connection slots, wrong portal details, or a source group that is down. Since a reinstall costs you the entry of credentials on a remote control, it belongs near the end of the order, not at the start. Test on a phone first. If the phone plays, reinstall on the stick with confidence, and keep the previous package on a USB stick so you can go back if the new build is the thing that broke it. Installs are unlimited across devices, so testing elsewhere costs nothing.