Buckingham Palace released an official statement congratulating Prince Harry and Meghan Markle on the birth of Baby Sussex. The congratulatory statement intentionally did not mention Meghan’s father, Thomas Markle Sr., which enraged royal watchers. But the Palace has a reason for excluding the Duchess of Sussex’s estranged dad.

Prince Harry and Meghan recently welcomed their firstborn, whose name is not yet announced. And the Sussexes received greetings from happy fans and famous people for the birth of their baby boy.

Former US First Lady Michelle Obama greeted the two through Twitter. “Congratulations, Meghan and Harry! Barack and I are so thrilled for both of you and can't wait to meet him,” the message read.

“Suits” actor Patrick J. Adams teased about a hashtag playdate, while Ryan Seacrest greeted Prince Harry and Meghan in a “Game Of Thrones” way.

Ellen DeGeneres also happily sent her greeting, joking that like Baby Sussex, she is also seventh in line — seventh in line for the key-making kiosk at her grocery store, that is.

Buckingham Palace also sent warm greetings over Baby Sussex’s arrival. “The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, The Duke and Duchess of Cambridge, Lady Jane Fellowes, Lady Sarah McCorquodale and Earl Spencer have been informed and are delighted with the news,” reads the official statement via Twitter.

The Palace also mentioned Meghan’s mother, Doria Ragland, in a second tweet. “The Duchess’s mother, Doria Ragland, who is overjoyed by the arrival of her first grandchild, is with Their Royal Highnesses at Frogmore Cottage. Her Royal Highness and the baby are both doing well,” says the tweet.

However, royal watchers were quick to notice that the announcement did not acknowledge Meghan’s father, Thomas Markle Sr. The Twitterverse were keen to label the House of Sussex, particularly Meghan, as disrespectful and disgraceful.

But Buckingham Palace may have a reason for not including Markle Sr. in the list of people who are important to Baby Sussex’s life. The 74-year-old father and grandfather remains “persona non grata” in the royal family.

Royal expert Katie Nicholl explained that Markle Sr. has yet to learn to keep family issues private. Markle Sr. has to prove that he is sincere in making amends with Meghan if he really wants to reach out to his grandson.

Prince Harry and Meghan Markle Prince Harry, Duke of Sussex, and Meghan, Duchess of Sussex, walk through the walled public Andalusian Gardens. Facundo Arrizabalaga - Pool/Getty Images