The on Monday suspended Midami Japanse Restaurant's liquor license for three days starting in September, after the restaurant last month.
The ran a sting on all alcohol-serving restaurants and three liquor stores. Midami, 444 Massachusetts Ave., was the only alcohol-serving establishment to have failed the test, according to police.
A Midami manager told the selectmen on Monday that a new employee failed to check the underage operatives' identifications due to lack of experience.
Town Counsel Juliana Rice said a three-day suspension conforms to the town's policy on first-time alcohol compliance violations.
The suspension will be enacted in September, when the restaurant will be unable to sell alcoholic beverages from Wednesday to Friday, though dates are yet to be determined. Midami will still be allowed to sell food.
The vote to suspend Midami's license for three days was unanimous.