Hillary Clinton has canceled a trip she was scheduled to take to California on Monday for fundraising and other campaign events, an aide said, declining to provide further details about her schedule for the week.

The presidential candidate of the Democratic Party cancelled the trip hours after doctor said on Sunday that she had pneumonia.

Mrs Clinton fell ill at a September 11 memorial, an episode that renewed focus on her health less than two months before the election.

Reuters reports that Clinton, 68, was diagnosed on Friday but her condition only came to light several hours after a video on social media appeared to show her swaying and her knees buckling before being helped into a motorcade as she left the memorial early Sunday.

Clinton had a medical examination when she got back to her home in Chappaqua, New York, according to a campaign aide. Her doctor, Lisa Bardack, said in a statement that she has been experiencing a cough related to allergies and that an examination on Friday showed it was pneumonia.

“She was put on antibiotics and advised to rest and modify her schedule. While at this morning’s event, she became overheated and dehydrated. I have just examined her and she is now re-hydrated and recovering nicely,” Bardack said.

Clinton’s pneumonia diagnosis comes at a crucial time in the White House race against Republican rival Donald Trump, who refrained from commenting on her health on Sunday.

The first of three presidential debates is on Sept. 26 and the election is on November 8.

Democratic National Committee head Donna Brazile said she was encouraged that Clinton “already is feeling better” and looked “forward to seeing her back out on the campaign trail and continuing on the path to victory.”