Think of it as you sharing a house with other people. You all have your own rooms (subdomains) but live at the same address (domain). You try to order a takeaway but they’ve blacklisted your address because another resident abused their service
Iptv is one of them things that you just have to keep trying a bunch until you get a reliable one. No one is going to give out their provider because it just increases the risk they go downhill or even get outright busted