If the add-on opens but shows zero channels, the M3U playlist URL itself is the most likely fault, either it's mistyped, expired, or pointed at the wrong path. If the list loads but individual channels won't play, the playlist parsed fine and the fault has moved downstream to the stream URLs themselves or your connection. These are different problems with different fixes, so check which one you actually have before changing any setting in the add-on. A blank list means the fault is entirely in that one URL field, while a populated but unplayable list points you toward the stream and your network instead.

The EPG (electronic program guide, the on-screen schedule) uses a separate XMLTV address from the channel playlist, and IPTV Simple Client matches guide entries to channels by an ID field that has to line up exactly between the two files. A mismatch there leaves channels playing perfectly with a blank or wrong guide, which looks like a bigger fault than it is. Re-entering the EPG URL and confirming the update interval in the add-on's settings resolves most of these. It's a narrow, fixable mismatch, not a sign anything is wrong with your subscription or the channels themselves.

Kodi version updates occasionally change how PVR add-ons like IPTV Simple Client load or how they handle cached data, which is a distinct and recurring cause separate from anything about your playlist or your service. If the add-on worked before a Kodi update and stopped right after, check the add-on's own version against what the current Kodi release expects, and clear its cached data before re-entering your playlist URL. This timing match, working before the update and broken right after, is usually enough on its own to confirm the cause.

Test the same M3U URL directly in VLC or another player on the same network. If it plays there, the fault is scoped to how IPTV Simple Client is parsing or caching the playlist, not your line or your internet. If it fails in VLC too, the problem sits upstream of the add-on entirely, and no setting inside Kodi will fix it. This cross-check takes under a minute and rules out half the guesswork, and it's the same test worth running any time a player app of any kind starts behaving strangely.