The pop icon, 61, shared a video clip Sunday from her Saturday show, thanking fans for the first of several scheduled performances in Portugal's capital and apologizing for canceling that night.
"Thank you again Lisbon!" she wrote. "Sorry I had to cancel tonight but I must listen to my body and rest!!"
Madonna did not elaborate on what led her to cancel, though the singer has previously canceled shows due to unspecified injuries. She expressed hope that she would be back onstage Tuesday and is scheduled to perform at The Lisbon Coliseum through Thursday.
"See you on Tuesday fingers crossed," she added. The venue offered refund requests until Tuesday and apologized for "the disappointment to fans."
This isn't the first time on this tour Madonna has had to cancel shows: Her Madame X North American tour run ended a day early in December after the "Like a Virgin" artist canceled her final show scheduled in Miami.
She took to social media two days later to say unspecified injuries caused her pain that "has been indescribable for the past few days." To illustrate her point, she shared a video from the final North America performance, which took place Dec. 21.
"With every song I sang, I said a prayer that I would make it to the next and get thru the show. My prayers were answered, And I made it," she wrote. "I consider myself a warrior. I never quit, I never give in, I never give up!! However this time I have to listen to my body."
'The pain I'm in right now is overwhelming': Madonna cancels three Boston concerts
She noted that her doctors told her she needed time to rest before continuing the tour.
In October, the pop star had to postpone a New York show at the last minute to recover from injuries.
A month later, she canceled three shows in Boston to "rest and follow doctor's orders" after "overwhelming pain."
And Madonna postponed the beginning of her Madame X tour. She was scheduled to kick off shows in Brooklyn on Sept. 12, but the tour was pushed back "as a result of the highly specialized production elements being delayed."
Contributing: Rasha Ali
This article originally appeared on USA TODAY: Madonna apologizes to fans after canceling another Madame X tour show