If you are unable to connect to a secure website (one that has https:// instead of http:// as the protocol prefix in its address), it is possible that A4Proxy attempts to establish a secure connection via a proxy which doesn’t support the secure protocol (Secure HTTP, HTTPS). Please look at the proxy list (Proxy Check tab), scroll the table to the right to see the HTTPS column. ‘X’ in this column indicates that the proxy supports Secure HTTP protocol. Make sure that the proxy selected as default does have an X in this column.
In order to test proxies for HTTPS support, you should enable the option “Check for FTP/HTTPS support on reset data” (Options menu, Special Options dialog box) and enable the “Reset Data” option on the Proxy Check tab before checking proxies.
It is also important that you enter the same proxy settings (127.0.0.1 port 80, redirecting requests from your browser to A4Proxy) in all three protocols in the proxy settings of your browser – i.e. in HTTP, Secure HTTP and FTP. See the details on configuring your browser at http://www.inetprivacy.com/a4proxy/support.htm