President Donald Trump continues to lash out at companies and business leaders on Twitter, and this time, it's Shark Tank investor Mark Cuban.

On Sunday morning, Trump tweeted that Cuban "backed me big-time but I wasn't interested in taking any of his calls. He's not smart enough to run for president!" Cuban replied with a simple "LOL," before replying to a Twitter user that he didn't know why Trump was tweeting at him:

The Dallas Mavericks owner has previously praised Trump for his "honesty," and had said that he would be open to running as his vice president, but he became increasingly critical of him as the presidential campaign went on. By July, he expressed his endorsement for Democratic nominee Hillary Clinton. Cuban said that while Trump had an "opportunity," he thought he had gone "off the reservation" with some of his remarks.It remains unclear what provoked Trump to snipe at Cuban on Sunday, though Cuban did give an interview to the Fort Worth Star-Telegram on Friday, in which he said that he didn't think Trump would last a full four years as president, and urged CEOs of public companies to "be an American citizen first," and to not be afraid to get involved in politics. "In the bigger scheme of things, our country benefits from peaceful activism a lot more than it benefits from one more shoe being sold, or one more basketball ticket being sold, for that matter," he added. And on Sunday, the New York Post reported that Trump's strategists believe it's possible that Cuban may be among Trump's foes in 2020.