In a March 2015 interview, President Obama said that he had learned about Hillary Clinton’s use of a private email server as secretary of state “the same time everybody else learned it, through news reports.”

But that assertion concerned aides of Mrs. Clinton, who knew that the president himself had received emails from the private address, according to a hacked email made public on Tuesday by WikiLeaks.

“We need to clean this up — he has emails from her — they do not say state.gov,” Cheryl D. Mills, a top aide, wrote to John D. Podesta, another senior adviser, on March 7, 2015.

Two days later, Mr. Obama’s spokesman, Josh Earnest, tried to clarify the president’s remarks, saying that he had, in fact, exchanged emails with Mrs. Clinton through her private account. But Mr. Earnest suggested that the president had no idea the emails could be a problem because he had relied on Mrs. Clinton to make sure that using a private account did not break any laws.