Frozen video on Zoom is caused by either network issues or CPU overload. Check your network first: run a speed test and look at upload speed (need 1.5+ Mbps for 720p) and packet loss (should be under 1%). If the network is fine, check CPU usage in Task Manager (Windows) or Activity Monitor (Mac) — if CPU is above 85%, Zoom can't encode video fast enough. Close browser tabs and apps you're not using. Disable virtual backgrounds and video touch-up, which are CPU-intensive. If you're on Wi-Fi, switch to Ethernet. In Zoom Settings > Video, uncheck HD and disable "Optimize for 3rd party video editor" in Advanced settings. Update your graphics drivers. If your computer is older, consider using Zoom's phone app for video while handling screen sharing from your computer.
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