This is a setback for Aereo‘s effort to carry broadcasters’ programming for relatively low fees. The U.S. Copyright Office says it “does not believe Aereo qualifies” for a designation as a cable service, which would enable the streaming service to have what’s known as a compulsory license to offer broadcast signals with fees set by the government. Internet transmissions of over-the-air TV “fall outside the scope” of the copyright rules that apply to cable companies; they just apply to services “regulated as cable systems by the FCC,” the arm of the Library of Congress said in a letter sent to Aereo yesterday.

Last month the U.S. Supreme Court said that Aereo can’t stream broadcast signals without payment because it seemed to resemble a cable distributor — which would be legally bound to pay to retransmit local TV stations. Even so, the Copyright Office says that “We do not see anything in the Supreme Court’s recent decision…that would alter” its view that the rules just apply to companies that the FCC deems to be cable systems. That could backfire on Aereo: FCC-designated cable companies are governed by communications laws that require them to negotiate fees directly with broadcasters.

The Copyright Office said that, since courts are still weighing Aereo’s status, it will accept the company’s filings on a provisional basis but not process them. On review it may make a more definitive decision “which could include rejection of the statements.”

Aereo declined to comment.