Why pncs Eugene's and pncs Beatrice's mother Sara was not invited on the royal wedding?

Sara Ferguson, Fergie as she is known has been "out of favor" with the royal family for a long time with her antics; but, the "straw that broke the camel's back" so to speak was when she tried to sell rights to access to her former husband, Prince Andrew and accepted money for offering to help make this possible (what her plan was, I don't know how) but, the press has coverage of the exchange of the transaction and the wording and it shows Fergie leaving with a brief case of money. You do not, do not violate the privacy of the royal family in any way, so she literally "cut her own throat".