Packet loss causes choppy audio and frozen video on calls. First, determine if the issue is local or ISP-side: connect directly to your modem via Ethernet (bypassing your router) and run a jitter test. If packet loss disappears, your router is the problem — restart it, update firmware, or replace it. If packet loss persists on Ethernet, contact your ISP. For Wi-Fi packet loss: move closer to the router, switch from 2.4GHz to 5GHz, and reduce interference from other devices, microwaves, and neighboring networks. Change your Wi-Fi channel to a less congested one (use a Wi-Fi analyzer app to find the best channel). Enable QoS (Quality of Service) on your router to prioritize video call traffic. Keep network utilization below 80% — if others on your network are streaming or downloading, their traffic can cause your packets to drop.