N.Y. Lien Law § 11-B
Within five days before or within thirty days after filing a notice of lien in accordance with section ten of this chapter or the filing of an amendment of notice of lien in accordance with section twelve-a of this chapter the lienor shall serve a copy of such notice or amendment by certified mail on the contractor, subcontractor, assignee or legal representative for whom he was employed or to whom he furnished materials or if the lienor is a contractor or subcontractor to the person, firm or corporation with whom the contract was made. A lienor having a direct contractual relationship with a subcontractor or a sub-subcontractor but not with a contractor shall also serve a copy of such notice or amendment by certified mail to the contractor. Failure to file proof of such a service with the county clerk within thirty-five days after the notice of lien is filed shall terminate the notice as a lien. Any lienor, or a person acting on behalf of a lienor, who fails to serve a copy of the notice of lien as required by this section shall be liable for reasonable attorney's fees, costs and expenses, as determined by the court, incurred in obtaining such copy.
N.Y. Lien Law § 11-B