If you connect to the internet through a proxy server, your proxy settings can be entered after checking the Use a proxy server box.
If you don't connect through a proxy, you should leave the Use a proxy server box unchecked to ensure PrintableCal can correctly connect to the internet.
Specify a Proxy Server
If you have configured Microsoft Internet Explorer to access the internet through a proxy server, you can simply have PrintableCal reuse those settings. Otherwise, you can choose to manually specify a proxy server and port by clicking the Specify a proxy server option.
Proxy Server Authentication
If your proxy server requires authentication to connect, check the Proxy server requires authentication box. This will allow you to enter the username, domain (optional), and password that are required to connect.