Problem with C# calling ActiveDirectory's SetPassword function

I create a new user successfully, and then I try to set their initial password using the following code:

newUser.AuthenticationType = AuthenticationTypes.Secure;
newUser.Invoke("SetPassword", new object[] { "som开发者_JS百科epassword" });
newUser.Properties["LockOutTime"].Value = 0; //unlock account

When it (eventually) returns, I get the following exception

System.IO.FileNotFoundException: The network path was not found

If I inspect the 'newUser' object, it has a Path attribute which looks fine to me.

I don't think my instance of AD is available over SSL though, I can only connect to it over port 389. Is that something to do with it?

Any help appreciated, I'm new to AD and struggling...

Thanks

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As suggested here, you might have more success with the new and improved System.DirectoryServices.AccountManagement namespace.

// establish context for local machine 
PrincipalContext ctx = new PrincipalContext(ContextType.Machine);

// find the account
UserPrincipal user = UserPrincipal.FindByIdentity(ctx, "YourUser");

// set the password to a new value 
user.SetPassword("new-top-secret-password"); 
user.Save();

marc_s provides more detail in the OP.