On several servers, running IIS 6 or IIS 7.5, from Windows Server 2003 or Windows Server 2008, when I view a certificate, I can see that I have warning signs on "Key Usage" and "Basic Constraints". When I had that verified by the certificate authority, they said they detected that SSLv2 was in effect and this could cause such reaction. To disable SSLv2, it was recommended to go in the Registry in the System\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0 and add a key Enabled with value 0. Then a reboot was necessary. After the reboot, this does not change anything.
Would there by anyone who would know how to resolve those two warning signs? Also, if you check some of your certificates, are you having those warning signs?
This support has been upscaled to SSLv3 since IE5. So, it has been a very long time that all major browers support SSLv3. SSLv2 has been known to have security issues. Some, there is a potential intrusion in there. This is why many are disabling SSLv2 at the server level.