Adding User to AD Security Group fails after user creation

I am using a WCF service to expose certain Active Directory management functions to our help desk staff without giving them the group membership required to manipulate AD directly. Adding users to and removing users from groups is working like a champ with existing users, but every time I create a new user it throws back this fun code:

The server is unwilling to process the request. (Exception from HRESULT: 0x80072035)

The code I use to add the user to the group is

    public bool AddGroupToUser(string userDn, string groupDn)
    {
        try
        {
            DirectoryEntry groupEntry = LdapTools.GetDirectoryEntry(groupDn);
            groupEntry.Properties["member"].Add(userDn);
            groupEntry.CommitChanges();
            groupEntry.Close();
            return true;
        }
        catch (DirectoryServicesCOMException)
        {
            return false;
        }
    }

Everything I've read on the subject is rather vague and I can't seem to find out WHY the exception is being triggered. Any ideas?

UPDATE

This is the code I use to create the user in AD:

        try
        {
            DirectoryEntry container = GetDirectoryEntry(storageOu);
            DirectoryEntry newUser = container.Children.Add("CN=" + employee.FullName, "user");
            newUser.Properties["sAMAccountName"].Value = employee.Username;
    开发者_StackOverflow中文版        newUser.Properties["displayName"].Value = employee.FullName;
            newUser.Properties["givenName"].Value = employee.FirstName;
            newUser.Properties["sn"].Value = employee.LastName;
            newUser.Properties["department"].Value = departmentName;
            newUser.Properties["userPrincipalName"].Value = employee.Username + "@APEX.Local";
            newUser.CommitChanges();

            newUser.Invoke("SetPassword", new object[] { employee.Password });
            newUser.CommitChanges();

            AdsUserFlags userSettings = AdsUserFlags.NormalAccount;
            newUser.Properties["userAccountControl"].Value = userSettings;
            newUser.CommitChanges();

            ldapPath = newUser.Path;

            newUser.Close();
            container.Close();
        }
        catch (DirectoryServicesCOMException e)
        {
            // Something went wrong... what???
        }
        catch (Exception e)
        {
            // Something else went wrong
        }

The new user can login, and can be manipulated using the standard MS tools.

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Apparently, unless I'm missing an important step here, the issue is time. When forcing the system to sleep for 8 seconds before attempting to add groups to the new user the process works. If I do it any sooner than the 8 second mark it fails.

I'm marking this answer as correct unless anybody can provide me a better solution.

---

Try:

 public bool  AddUserToGroup(string userName, string groupName)

        {

            bool done = false;

            GroupPrincipal group = GroupPrincipal.FindByIdentity(context, groupName);

            if (group == null)

            {

                group = new GroupPrincipal(context, groupName);

            }

            UserPrincipal user = UserPrincipal.FindByIdentity(context, userName);

            if (user != null & group != null)

            {

                group.Members.Add(user);

                group.Save();

                done = (user.IsMemberOf(group));

            }

            return done;

        }

Reference:
http://www.c-sharpcorner.com/UploadFile/dhananjaycoder/activedirectoryoperations11132009113015AM/activedirectoryoperations.aspx

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As it mentioned in here, can you tell us that you set the password of the newly created users? In the reference, it says that you should SetPassword of the user before doing anything with it.

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Time issue could occur from a Active Directory replication issue.

Once, I gave a product to my customer which creates user over Active Directory, which has over 10.000 records in it, with the given informations on a SharePoint form and then program adds the user to a SharePoint group. The problem was, SharePoint throws an error about the newly created user, it says user does not exist in AD.

So, one of out system engineer told us about the replication opearation on the Active Directory that it could be the source of the problem and it was true.

For the solution, program tries to do the job for 10 times with 1 second sleeps. No problem occurred so far. So as a solution, I would suggest you to check out the AD for the existence of replication method.

P.S: When I asked questions to my customers system engineers about the replication operation, they all rejected the existence of AD replication operation and told me that the program has the problem. They believed me when we created a new user in AD from a computer, we couldn't see the user for 5 seconds on an another computer.