Principal Extension for UserPrincipal in .NET throwing an "Unwilling to process request" error

Question

I am trying to set the value of an extension attribute in AD with my VB.NET executable. I extended the UserPrincipal class to accomplish this but now I get an error

The server is unwilling to process the request

when I try to set the extended property.

I can get that property from an existing user in AD without any errors and when I try to create and save the user without the extended class it works.

        Dim stringDomainName As String = System.Net.NetworkInformation.IPGlobalProperties.GetIPGlobalProperties().DomainName
        Dim objPrincipalContext As New PrincipalContext(ContextType.Domain, stringDomainName, DirectoryPath, ContextOptions.SimpleBind, DomainUsername, DomainPassword)
        Dim objUserPrincipal As New UPExtention(objPrincipalContext, sUserName, sPassword, True)

        Dim expDate As Date

        'Set Name
        objUserPrincipal.Name = sFirstName & " " & sLastName
        'Set First Name
        objUserPrincipal.GivenName = sFirstName
        'Set Last Name
        objUserPrincipal.Surname = sLastName
        'Set Display Name
        objUserPrincipal.DisplayName = sLastName & ", " & sFirstName
        'Enable Account
        objUserPrincipal.Enabled = True
        objUserPrincipal.extentionAttribute15 = sUserName

        'Save the created user
        objUserPrincipal.Save(objPrincipalContext)

Answer 1

I'm not 100% sure what was causing the error but I went back to using the unextended UserPrincipal class to create the initial object and saved it without setting the extension attribute. Then I created an object of the extended UserPrincipal and used the overloaded FindByIdentity function to get the user I just created and then set the extension attribute and saved again. Now it works!