Why do I get I/O errors, or the message "Netscape has encountered bad data from the server", when connecting via HTTPS to an Apache+mod_ssl server with Netscape Navigator?

This usually occurs when you have created a new server certificate for a given domain, but had previously told your browser to always accept the old server certificate. Once you clear the entry for the old certificate from your browser, everything should be fine. Netscape's SSL implementation is correct, so when you encounter I/O errors with Netscape Navigator it is usually caused by the configured certificates.