I have an API hosted in IIS using a wildcard cert provided by a client. The Cert is for *.myclient.com. However they want me to connect via the public IP address. When I attempt to call my API, I'm getting the following error:

Can't connect securely to this page

This might be because the site uses outdated or unsafe TLS security settings. If this keeps happening, try 
contacting the website's owner.

Is this because I'm trying to use an IP address when the cert specifies a domain? Or is this due to some other problem?

I've also attempted enabling TLS 1.2 for IIS, which didn't appear to change anything.

Any help would be greatly appreciated.

  • 1
    "Is this because I'm trying to use an IP address when the cert specifies a domain?" That's likely at least part of the problem. Most TLS-enabled applications will require a match between the name (or names) in the certificate and the name you use to connect to the server. If the certificate uses a hostname, but you connect using an IP address, you'll have a mismatch and the application will either warn you about it or refuse to connect. – Doug Deden Jan 31 at 21:20
  • "they want me" Convince them that it is not a good idea to use IP address. – Lex Li Jan 31 at 22:18

The issue is that your certificate does not provide an ipaddress SAN for your site so the certificate is not valid when attempting to access it via the IP address.

I would recommend using the FQDN (Fully qualified domain name) of the site instead and then your certificate will already be valid.

If you absolutely need to access it via IP address then you will need to reissue your certificate and add an ipaddress SAN (subject alternate name) with your IP address.

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