Several factors can contribute to an HP printer not responding. Firstly, check the physical connections to ensure cables are securely plugged in. Network issues, like a weak Wi-Fi signal or incorrect settings, might hinder communication. Additionally, a print queue backlog or paper jams can impede functionality. It's crucial to verify that the printer is set as the default device on your computer. Moreover, software conflicts or firewall restrictions may affect communication between the printer and computer.