It looks like the cage match between Mark Zuckerberg and Elon Musk is off because—to no one's surprise—the two rival CEOs can’t agree on anything.

On Sunday, Zuckerberg called out Musk for essentially jerking him around and trying to delay the fight. According to him, Musk first wants to hold a practice match at a fighting cage at Zuckerberg’s home before staging the official public bout.

“I think we can all agree Elon isn't serious and it's time to move on,” Zuckerberg posted on his rival social media platform, Threads. “I offered a real date. Dana White (UFC president) offered to make this a legit competition for charity. Elon won't confirm a date, then says he needs surgery, and now asks to do a practice round in my backyard instead.”

The offer from Musk to hold a practice fight at Zuckerberg’s house is real, according to the author Walter Isaacson, who is writing a biography about the Tesla CEO. As evidence, he posted a screenshot showing the text exchange between the two tech CEOs. In it, Musk says he’ll be in Palo Alto, California, today. But he also concedes: “I have not been practicing much, apart from a brief bout with Lex Fridman.”

In his own post on Threads, Zuckerberg says it was up to Musk on whether he was ready to throw down. He then posted a photo of himself sparring inside his backyard fight cage.

“If Elon ever gets serious about a real date and official event, he knows how to reach me,” he added. “Otherwise, time to move on. I'm going to focus on competing with people who take the sport seriously.”

In response, Musk tweeted that “Zuck is a chicken." In a later tweet, Musk joked about swinging by Zuckerberg's home anyway. “Can’t wait to bang on his door tomorrow."