Help with clicking a button inside a popup

[xenaree]

Hi all, i'm facing this problem when i can't find a way to click this "OK" button (the blue one).

The' application i'm automating is the web application of the microsoft dynamics.

This is the popup :

 

I click a button from the parent window and this new window appears with the popup. I'm trying to click the OK button to close the popup

This is what the Autoit windows info gave me :

As you can notice, there isn't a Class:Button the summary.

The auto.MouseClick("LEFT", 1145, 185) works butit is not a good idea.

Also, i tried with 

var auto = new AutoItX3();
auto.WinActivate("Requeteur Oeuvre : Créer Requeteur Oeuvre - Google Chrome");
auto.Send(Keys.Enter);

The WinActive loses focus quickly.

 

Thank you for you help