IPTV may stop working after router or ISP changes because the new network assigns a different IP address, blocks certain ports, uses strict NAT, or applies firewall rules. Some IPTV providers lock accounts to a specific IP. Solutions include rebooting devices, disabling ISP firewalls, switching DNS, using a VPN, or contacting the provider to reset IP authorization. Glanfy recommends providers that support multi-network access without strict IP locking.