Since iCloud sync works on your other devices, the issue is specific to this PC. Check Apple’s System Status for outages, ensure date & time are set to auto-update, and clear the iCloud cache (C:\Users\YourUsername\AppData\Local\Apple Inc\iCloud\). Disable any VPN, firewall, or proxy, reinstall iCloud for Windows, and flush the DNS cache (ipconfig /flushdns). If the issue persists, try a different network. Let me know if this helps!