The news was featured on MSN.com: “Prominent Irish broadcaster faces trial over alleged sexual misconduct.” At the top of the story was a photo of Dave Fanning.

But Mr. Fanning, an Irish D.J. and talk-show host famed for his discovery of the rock band U2, was not the broadcaster in question.

“You wouldn’t believe the amount of people who got in touch,” said Mr. Fanning, who called the error “outrageous.”

The falsehood, visible for hours on the default homepage for anyone in Ireland who used Microsoft Edge as a browser, was the result of an artificial intelligence snafu.

A fly-by-night journalism outlet called BNN Breaking had used an A.I. chatbot to paraphrase an article from another news site, according to a BNN employee. BNN added Mr. Fanning to the mix by including a photo of a “prominent Irish broadcaster.” The story was then promoted by MSN, a web portal owned by Microsoft.

The story was deleted from the internet a day later, but the damage to Mr. Fanning’s reputation was not so easily undone, he said in a defamation lawsuit filed in Ireland against Microsoft and BNN Breaking. His is just one of many complaints against BNN, a site based in Hong Kong that published numerous falsehoods during its short time online as a result of what appeared to be generative A.I. errors.