By Ramishah Maruf, CNN

New York (CNN) — The future of Sports Illustrated was uncertain Friday after the publisher of the iconic magazine and website laid off most or “probably all” of its guild-represented staff, its union said.

In a memo sent to staff viewed by CNN, the magazine’s publisher said it is “laying off staff that work on the SI brand.”

Authentic Brands Group has owned the magazine and website since 2019. It sold the publishing rights to Arena Group, but the company missed a recent payment for those publishing rights and ABG revoked them, the publisher said in its memo.

“This is another difficult day in what has been a difficult four years for Sports Illustrated under Arena Group (previously The Maven) stewardship,” the union said in a statement on X. “We are calling on ABG to ensure the continued publication of SI and allow it to serve our audience in the way it has for nearly 70 years.”

Arena Group and a spokesperson for Manoj Bhargava, the 5-Hour Energy founder who owns a majority stake in Arena Group, did not immediately respond to a request for comment.

The union said it expects the Arena Group to honor its union contract and for all of its employees to be treated fairly.

“We have fought together as a union to maintain the standard of this stories publication that we love, and to make sure our workers are treated fairly for the value they bring to this company. It is a fight we will continue,” Mitch Goldich, NFL editor and unit chair, said in the union statement.

It’s been a difficult few months for one of the most recognized names in sports journalism – and the entire future of the brand is uncertain.

In December, the Arena Group fired Sports Illustrated’s CEO Ross Levinsohn after an embarrassing debacle in which Sports Illustrated was caught publishing stories with fake author names and profile photos generated by artificial intelligence. Levinsohn was replaced, effective immediately, by interim chief executive Manoj Bhargava, the 5-Hour Energy founder who owns a majority stake in The Arena Group, said Vince Bodiford, a spokesperson for Bhargava.

CNN’s Oliver Darcy and Liam Reilly contributed to this report.