Apple Mac Error -4403 unable to contact apple for Internet recovery.
While trying to Restore a Mac Mini to its original factory settings ( command +r )I came across this little gem, Error -4403. The Internet recover procedure failed because it was unable to access Apple due to the Barracuda Webfilter 810. Placing the 810 in audit mode allowed the recovery procedure to complete so the restore menu and utilities were available. So if you get this error and there is a proxy or other filtering device between your computer and the Internet try bypassing the devices or white-list the mac you are working on.