New York ? New York University officials weren’t laughing when hundreds of people mistakenly received word that they’d been accepted to grad school on April Fools’ Day.

NYU says it sent out acceptance e-mails April 1 to 489 applicants to the Robert F. Wagner Graduate School of Public Service. Those applicants should have received rejection letters instead.

The school sent out a second e-mail about an hour later to the applicants, saying they hadn’t been accepted after all.

NYU spokesman Robert Polner blamed the mixup on a clerical error.