OrganizationService error "Expected non-empty string. Parameter name: authenticationInfo"

Hi, all.

I am using custom WCF Service which invokes OrganizationService.Create method.

When I am using it from visual studio debug - it works well and successfully returns me guid of created record.
But when I am trying to call the same service hosted at IIS - it returns a strange error.

<s:Envelope xmlns:s="schemas.xmlsoap.org/.../envelope">
<s:Body>
<s:Fault>
<faultcode xmlns:a="schemas.microsoft.com/.../dispatcher">a:InternalServiceFault</faultcode>
<faultstring xml:lang="ru-RU">Expected non-empty string.</faultstring>
<detail>
<ExceptionDetail xmlns="schemas.datacontract.org/.../System.ServiceModel" xmlns:i="www.w3.org/.../XMLSchema-instance">
<HelpLink i:nil="true"/>
<InnerException>
<HelpLink i:nil="true"/>
<InnerException i:nil="true"/>
<Message>Expected non-empty string.
Parameter name: authenticationInfo</Message>
<StackTrace i:nil="true"/>
<Type>System.ArgumentException</Type>
</InnerException>
<Message>Expected non-empty string.</Message>
<StackTrace>at Microsoft.Crm.Exceptions.ThrowIfEmpty(String value, String parameterName)
at Microsoft.Crm.Authentication.UserManagementFactory.ValidateSpecialUser(String authenticationInfo, Guid organizationId)
at Microsoft.Crm.Authentication.UserIdentityAuthorizationManager.ValidateSpecialUser(String authenticationInfo, Guid organizationId)
at Microsoft.Crm.Authentication.ClaimsIdentityAuthorizationManager.CheckAccess(AuthorizationContext context)
at Microsoft.Crm.Authentication.WindowsIdentityAuthorizationManager.Authenticate(OperationContext operationContext)
at Microsoft.Crm.Authentication.WindowsIdentityAuthorizationManager.CheckAccessCore(OperationContext operationContext)
at System.ServiceModel.Dispatcher.AuthorizationBehavior.Authorize(MessageRpc&amp; rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc&amp; rpc)
at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)</StackTrace>
<Type>Microsoft.Crm.CrmArgumentException</Type>
</ExceptionDetail>
</detail>
</s:Fault>
</s:Body>
</s:Envelope>

I checked it and found - this exception comes from OrganizationService.
What can be the reason of such behaviour? Any ideas?