IPTV code blocked on a single computer

Good evening,

I have IPTV codes that only work on one PC. I have different codes for 3 users but I can't use them anywhere else than on my computer via IPTV SMARTER PRO. On another computer or on the TV, it says Invalid Details even though I enter exactly the same information and I'm not using the accounts anywhere else at that moment. Do you know where the issue might come from? Thank you.