If you are not able to access App Store, iTunes or any HTTPS websites on your Mac while in school but you are able to open normal (HTTP) websites its likely you will need to set the proxy for Secure Web Sites:
- Open System Preferences
- Click on Network Preferences
- Select your active network connection on the left panel and (WiFi or Ethernet) and click Advanced on the bottom right
- Choose the Proxies tab and find “Web Proxy (HTTP)” and check what you have set for “Web Proxy Server” in the right panel
- On the left select Secure Web Proxy (HTTPS) making sure you tick the box on the left and set the “Secure Web Proxy Server” to the same settings as in the “Web Proxy (HTTP)”
- Once you have set this you should be able to access secure websites with HTTPS in the address, such as Easymail and App Store.
Reviewed on 02/03/2018