No one warns you about deliverability. An IPTV Reseller Panel sends password resets, expiry reminders, and welcome guides through its own email system. If that system uses a shared IP address, and someone else on that IP sends spam, your British IPTV customers won't get their login credentials. What actually works is connecting your own SMTP provider—SendGrid, Postmark, even Gmail's API—to your panel instead of using their default mail server. Most operators discover this when their first 50 customers all say "I never received my password."
The pattern that keeps showing up across successful British IPTV resellers is simple: British IPTV operators with low churn rates all test their panel's email delivery weekly. Your IPTV Reseller Panel should let you send a test email to any address. Use that feature. Send one to your own Gmail, Outlook, and Yahoo accounts. Do they land in inbox or spam? I've watched resellers lose hundreds of pounds because their panel's emails were getting silently filtered into spam folders for six months before anyone noticed. Honestly, that weekly two-minute check is the highest ROI maintenance you'll ever do.