SSL Error when attempting to use custom jobs

Describe your question in as much detail as possible:
I’m currently hosting GitLab ee and I’ve run into an error when trying to set up a custom include job.

I have a repo with some .gitlab-ci.yml files in which I’m trying to include in another CI file in another repo.
When applying this configuration I get the error This GitLab CI configuration is invalid: SSL_connect returned=1 errno=0 state=error: certificate verify failed (unable to get local issuer certificate)

  • What are you seeing, and how does that differ from what you expect to see?
    The CI config should pass (screenshots below show the issue)

  • Consider including screenshots, error messages, and/or other helpful visuals

  • What version are you on? Are you using self-managed or

    • GitLab: 12.8.6-ee
    • Runner: 12.8.0
  • Add the CI configuration from .gitlab-ci.yml and other configuration if relevant (e.g. docker-compose.yml)

  - build

  • What troubleshooting steps have you already taken? Can you link to any docs or other resources so we know where you have been?
    I’ve taken no precautionary steps as I’m not sure what to do :slight_smile:

Extra Info:
I use CF Full SSL with Origin certs for GitLab.