A technical glitch took down a wireless network used by New York City’s municipal government, raising serious questions about security and reliability of operational technology used by the city.

The New York City Wireless Network, or NYCWiN, was initially deployed in 2008 at a cost of $500 million. It costs the city an additional $37 million per year to maintain. The stated purpose of NYCWiN is to “support public safety and other essential City operations.” The city uses the GPS-based system to manage license plate readers, as well as the monitoring of water meters and traffic lights among other applications.

NYCWiN was down on April 6, an outage caused by an issue similar to the Y2K bug. In this case, the system required resetting every 1024 weeks due to a memory capacity limitation involving calendar dates.

City officials have been less than transparent about the problem, raising concerns about government communications in general, but especially in the face of increasing attacks against government and municipal targets at the operations level.

“If the city’s paying $40 million a year to maintain software infrastructure, first, when it goes down, the Council and the public should know about it,” said Councilman Brad Lander to the New York Times.

Mayor Bill DiBlasio said the city was investigating who was responsible for the problem. Read more about the outage here.