Why does my certificate not work correctly with port 19638?

Port 19638 is the Administration port and runs another instance of Apache, therefore changes are required to a second config file. That file is siteX.ssl where X is the site number (usually 1). The same directives that appear in the httpd.conf file must also appear in the siteX.ssl file (ie SSLCertificateFile, SSLCertificateKeyFile and SSLCACertificateFile).