Elon Musk and Parag Agrawal, head of Twitter Inc., are at odds over the social media giant’s handling of so-called automated bots, fueling speculation that Musk may be trying to lower the price, or even his to walk away from a $44 billion bid for the company. Musk said at a tech conference in Miami that fake users make up at least 20% of all Twitter accounts, possibly as much as 90%. Twitter disagrees. It’s been reported that spam accounts make up less than 5% of all users, and Agrawal has posted a lengthy thread detailing his company’s methodology. Musk responded by tweeting, “This deal cannot go ahead” unless Twitter provides evidence to support his claims.