Your proxy server settings are configured in the browser properties. A proxy server provides a central location for an Internet connection. Companies use proxy servers to control internet traffic.
Do you have a fixed IP or DHCP , is the printer on wifi or LAN?
Try to reset the config on the printer.
maybe this will help :
http://h30434.www3.hp.com/t5/LaserJet-Printing/Web-Services-problem-Server-connection-error/td-p/926923
Kind regards,
kevin