Windows Activation Error (0x8004FE33)

Failed to activate with error 0x8004FE33
Failed to acquire a Confirmation ID with error 0x8004FE33

Basically our proxy requires authentication and was preventing activation.

These urls had to be excluded from unauthentication on the the proxy server (ISA) so that the certificate revocation lists could be accessed. (We allowed both HTTP & HTTPS).

crl.microsoft.com/pki/crl/products/MicrosoftRootAuthority.crl

crl.microsoft.com/pki/crl/products/MicrosoftProductSecureCommunications.crl

microsoft.com/pki/crl/products/MicrosoftProductSecureCommunications.crl

crl.microsoft.com/pki/crl/products/MicrosoftProductSecureServer.crl

microsoft.com/pki/crl/products/MicrosoftProductSecureServer.crl

activation.sls.microsoft.com:443