The 2nd US Circuit Court of Appeals in Manhattan ruled today, overturning a lower court decision.
The appeals court says that Congress did not intend a US law governing warrants to be enforced against a US-based service provider storing contents of a customer's electronic communications on servers outside the United States.
Prosecutors sought the information in December 2013, saying they believed the account in a Dublin facility opened in 2010 was being used to further narcotics trafficking.
US prosecutors said the US properly followed the law in requesting the information.