What role does Windows Firewall or third-party antivirus software play in Printer Error 709 on Windows 11, and how to troubleshoot it?

Windows Firewall or third-party antivirus programs can sometimes incorrectly block the communication between your PC and the printer, leading to Error 709. To troubleshoot, temporarily disable your antivirus software and the Windows Defender Firewall (via 'Settings' > 'Privacy & security' > 'Windows Security' > 'Firewall & network protection') and try printing. If it works, re-enable them and add exceptions for your printer's port (usually TCP 9100 for network printers or specific ports for other types) and any printer-related software in their settings.