Can software firewalls or antivirus programs cause a 'Brother printer not printing' error, and how do I check?

Yes, security software like firewalls or antivirus programs can sometimes block communication between your computer and printer, leading to 'not printing' errors, especially for network printers. To check if this is the cause, temporarily disable your firewall and/or antivirus software and try printing. If printing works, you'll need to add an exception for your printer's IP address or the printer software in your security software's settings. Remember to re-enable your security software afterwards.