The Justice Department doesn’t want the public to see its immunity deal with a former government employee who installed the private email server in Hillary Clinton’s basement.
It says its release could jeopardize an ongoing FBI probe.
Ex-State Department staffer Bryan Pagliano had been set to answer questions under oath this week.
The deposition was scheduled in a lawsuit filed by the conservative legal advocacy group Judicial Watch over access to emails sent and received by the presumptive Democratic presidential nominee when she was secretary of state.
Lawyers for Pagliano told a federal judge he would invoke his Fifth Amendment right against self-incrimination, citing his immunity deal.
In court filings, the government said releasing the deal could prematurely reveal the scope of its investigation into whether classified material was mishandled.