Windows 7 refuses to connect to 802.1X network if server certificate’s subject is empty

If the following are true…

  • Windows 7 connects to 802.1X enabled network
  • EAP method has something to do with TLS (PEAP, EAP-TLS…)
  • Server certificate’s subject field is empty

…then Windows 7 will refuse to connect with useless error messages. You’ll just have to know that Windows 7 doesn’t accept server certificate with empty subject. Some Certificate Services templates (Kerberos Authentication) keep subject empty by default so watch out if you have NPS on DC for example. Windows 8.1+ will work fine.

There’s little information about it online and the issue is quite hard to track down.