SSL on Domain Mapped Subsites

I have a subdomain which we are domain mapping to a URL

The DNS is mapped to the IP address for the server and all works well apart from the SSL. The subdomain where it actually lives ( ) is secure as we use LetsEncrypt on the server with wildcards to secure it, but obviously is not secure (or does not appear so) and throws warnings.

What is the best method for actually securing in these circumstances? Do I need to list as an add-on domain on the hosting server and issue a LetsEncrypt certificate from there or will it fail the ACME Challenge? Or do I somehow set up an SSL on the domain name elsewhere - perhaps with the DNS host?

  • Dimitris
    • Support Star

    Hello there Conor,

    hope you're doing good today and thanks for reaching us! :slight_smile:

    That is correct, as long as the SSL certificate supports wildcards of, it can't support domain.
    These kind of SSL certificates are called multi-domain certificates, but Let's Encrypt doesn't support these, at least for the moment.
    You should create an add-on domain in your server for the mapped domain and then create/assign a separate SSL certificate for that from Let's Encrypt.
    This should resolve this issue as any non-safe messages in browsers will be gone. Also any ACME files should be automatically generated, so you shouldn't have any issues with that also (in case you do, please contact your hosting provider about it).

    Hope that was some help!
    Warm regards,

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