A federal appeals court panel on Friday upheld the criminal conviction of Donald Trump’s longtime ally Steve Bannon for defying a subpoena from the House committee investigating the attack on the U.S. Capitol.

A three-judge panel of the U.S. Court of Appeals for the D.C. Circuit rejected Bannon’s challenges to his contempt of Congress conviction. Bannon had been sentenced to four months in prison, but the judge overseeing the case had allowed him to stay free pending appeal.

Bannon’s attorneys didn’t immediately respond to an email seeking comment. His lawyers could ask the full D.C. appeals court to hear the matter.

The congressional committee sought Bannon’s testimony over his involvement in Trump’s efforts to overturn the 2020 presidential election.

Bannon had initially argued that his testimony was protected by Trump’s claim of executive privilege. But the House panel and the Justice Department contend such a claim is dubious because Trump had fired Bannon from the White House in 2017 and Bannon was thus a private citizen when he was consulting with the then-president in the run-up to the riot .

A second Trump aide, trade advisor Peter Navarro, was also convicted of contempt of Congress and reported to prison in March to serve his four-month sentence.