Kodi presents a listing of add-ons through its official repository but there are thousands of extra add-ons accessible through different sources on the Internet. How to setup IPTV on KODI?
If the add-on on Kodi receives streams from only a single source (M3U), it would be possible that the source is down and in this case you have to wait for an update.
On the other hand, when the add-on is multi-source (Exodus, SALTs), the reason would be one of the following: you have not installed the add-on directly from the repo or you have picked an uncommon movie/TV show that has no streams available. What is a Kodi add-on?
How can I fix the out of order Adds-on on KODI?