The Academy of Motion Pictures Arts and Sciences has voted to rescind the sound mixing nomination for Greg P Russell for his work on 13 Hours: The Secret Soldiers of Benghazi.
The decision, announced on Saturday, was due to Russell's violation of Academy campaign regulations.
The statement says Russell violated strict rules applied to telephone lobbying.
Academy President Cheryl Boone Isaacs said in a statement that they take "very seriously the Oscars voting process".
13 Hours is still eligible for the award, but only for mixers Gary Summers, Jeffrey J Haboush and Mac Ruth.
At today's Oscars, the 13 Hours crew is competing against the sound mixing team from Arrival, Hacksaw Ridge, La La Land and Rogue One: A Star Wars Story.