A single channel stuck on a loading spinner while everything else plays fine is a source problem for that one stream, not a Firestick problem and not your internet. The fix isn't on your end: switch away to a working channel and back. If it recovers, the session for that one channel had stalled and reconnecting cleared it. If it stays dead after several tries, that one source is down and no local setting changes it. This single test discriminates a local fault from a source fault faster than any restart.

When every channel inside one group loads but nothing in a different group does, the fault is server-side for that category specifically, not the app or your connection. A live stream arrives as roughly six-second segments; if the server delivering that group stalls longer than the app can buffer, every channel fed from it freezes together while unrelated groups keep playing normally, since they're served from a different source entirely. There's nothing to fix locally here beyond waiting it out or switching to a working category in the meantime, since no router or account setting reaches a stall happening on the server side.

A full-app failure points at the player itself or your line, not a single stream. Player apps hold the entire visible channel list in memory, and lists pushing past roughly 18,000 visible channels start to destabilize on Firestick hardware specifically, which has less memory headroom than a phone or smart TV and can look exactly like nothing loading at all. Hiding unused channel groups in the app settings trims what's loaded into memory and is a genuine fix here, separate from any router or bandwidth troubleshooting you might try first.

A sudden full-app failure right after a Firestick or app update, with nothing else changed on your network or account, is a distinct and common cause on its own: the update regressed something in how the app talks to the server or renders the list, rather than exposing a problem that was already there waiting to surface. Rolling back isn't usually possible on Firestick, since the app store doesn't offer older versions, but clearing the app's cache and data, then relaunching and logging back in, resolves most post-update regressions without needing to reset the whole device or reinstall from scratch.