Carey shared on Twitter selfies with the Clintons on Monday and referred to Hillary Clinton as President in her caption.
"An honor to meet President Clinton and her husband, former President Bill Clinton!" the Grammy-winning singer and actress tweeted. "Thank you for everything you have done and continue to do for our country."
Some fans saw Carey's tweet as a diss aimed at President Trump.
Hillary Clinton received more votes for President in 2016 than Donald Trump, who won the Electoral College to take office.
Clinton, former Secretary of State in the Obama administration, was the first woman nominated for President by a major party.