As reports the edition Express, 53-year-old Samantha tried to get into Kensington Palace, which is now home to her younger sister. However, the guard informed her that he could not accept it personally and she was advised to leave it in the mailbox outside the palace.
The timeline of Markle embarrassment moves in peaks and troughs, with the silence likely worrying the palace in regards to what the next Markle move will be.
Samantha, 53, flew into the United Kingdom with the aim of confronting her half-sister but pictures appear to show her being met with a wall of silence after an embarrassing stand-off with palace security. However, arrived in a wheelchair an American (she suffers with multiple sclerosis in 2008), did not let the Palace guards.More news: Saudi Arabia unable to replace lost Iranian oil - Iran’s oil minister
But, on Sunday, Samantha teased her Twitter followers, writing, "Everybody would love to know what's in that letter".
Samantha has been demanding a meeting with the Duchess of Sussex and her husband since she was snubbed from the royal wedding in May.
"There is so much water under the bridge and so much has spun out of control that was never meant to", she explained.
Just days after the couple's wedding on May 19, he said: "I think that even before Meghan has learned how to spell Leicester and Torquay she'll be starting a family. I can't give the details of that but I really wanted the world and really my sister and the British Royal family to know what happened and know the truth about a lot of things".