Fans reportedly received an e-mail from Ticketmaster saying, "It is not possible to confirm new dates at the present time so we are refunding all ticket holders."
A representative for Jackson did not immediately respond to a request for comment.
Jackson had reportedly been in Europe prepping for the latest leg of her Unbreakable World Tour, which was set to begin March 26th in Dubai, followed by a March 30th gig in Birmingham, U.K. The European trek was slated to run through early May, with Jackson then returning to North America for a string of dates.
The Unbreakable World Tour has been plagued by cancellations. In October, Jackson called off a string of shows to rest her vocal cords, and then postponed her winter dates so that she could undergo an unspecified surgery. While Jackson did not say whether the surgery was related to her previous ailment, she did dispel rumors in January that she was suffering from cancer.
Those called-off winter dates will now take place throughout the summer, starting July 1st at the Pepsi Center in Denver, and wrapping August 8th at the Quicken Loans Arena in Cleveland. Tickets for all previously announced dates will be honored at the rescheduled shows.
Unbreakable, Jackson's first album in seven years, was released in October. The LP debuted at Number One on the Billboard 200, making it her seventh career LP to hit the top spot. The milestone also placed Jackson among Bruce Springsteen and Barbra Streisand as the only artists to have scored Number One albums in the 2010s, 2000s, 1990s and 1980s.