Using Self-Signed SSL Certificates

By default, all machines in a CircleCI Enterprise installation verify SSL certs for the GitHub Enterprise instance. If you’re using a self-signed cert, or using a custom CA root, you can select the “HTTPS (with self-signed certificate)” option in the System Console at port 8800. You also need to export on builder machines (replacing below with the host of your GitHub Enterprise instance).

See this doc for details on setting builder machine environment variables.