CRM 2013 IFD Object reference not set to an instance of Obje

ncalixto

After instaling and configuring IFD on Dynamics CRM 2013, we are unable to access CRM. On ADFS page after insert username and password, adfs page presents an error. After some investigation we've found an error on event viewer of adfs on adfs server. The error is the folowing:
Microsoft.IdentityServer.RequestFailedException: MSIS7012: An error occurred while processing the request. Contact your administrator for details. ---> System.TypeInitializationException: The type initializer for 'Microsoft.IdentityServer.Service.SecurityTokenService.MSISSecurityTokenService' threw an exception. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.DeviceRegistration.ADAdapter.ADStore.GetDnsHostNameFromNtdsSettingDN(IDRServerContext context, String distinguishedName)
at Microsoft.DeviceRegistration.ADAdapter.ADStore.FindAllGCsInDomain(IDRServerContext context)
...

Does anyone already faced this error and can point me on any direction?
To install and configure IFD we folowed the folowing guide:
http://blogs.msdn.com/b/niran_belliappa/archive/2014/01/16/step-by-step-configuring-crm-2013-internet-facing-deployment-ifd.aspx

Thanks,