AT&T and the U.S. Department of Justice have been unable to resolve antitrust concerns over the pending Time Warner acquisition outside of court, according to a document filed today.

The two sides have been engaging in settlement talks, but “despite their efforts, have not been able to settle the matter.” The disclosure came in a document laying out a schedule leading up to the planned March 19 trial.

The Justice Department is suing to block the merger, arguing that the combination of the nation’s largest television distributor and one Hollywood’s leading studios would be bad for consumers and competition.

AT&T is fighting to preserve the $85 billion deal, arguing that the DOJ’s position on the deal “stretches the very reach of anti-trust law beyond the breaking point” and upends 50 years of precedent.