Arrow-player.com is neither listed as a supported site for StreamFab M3U8 or MPD. Furthermore, there is no extractor found within yt-dlp for it, as well, which is key to making it supported by StreamFab. I'm afraid that you're going to have to wait quite a bit longer until yt-dlp feels it is worthwhiled to make an extractor for it.
Cats4U
The fact that he said it used to work in a previous version means that it probably uses an extractor for a licensed content delivery system.
Like, for example, Channel 4, Showtime, SXSW, and UKTV use Brightcove and WEtv uses AMCNetworks. I don't have a subscription so i can't check and see what extractor it would need but it's probably not Brightcove as UKTV uses that and it's apparently working now.
I wonder if they only rely on yt-dlp extractors... The generic extractor can also work on sites that don't do anything special and it's a straightforward .mpd or .m3u8.
