Flynn has said he does not remember talking in late 2016 with the Russian ambassador about sanctions. But the transcripts showed that the sanctions were the central discussion point between the men. https://www.nytimes.com/2020/05/29/us/politics/flynn-russian-ambassador-transcripts.html?smid=tw-share

Flynn had admitted to lying to the F.B.I. about talking to Mr. Kislyak about Russia’s vote on an impending United Nations resolution to condemn Israeli settlements in the West Bank.

Mr. Kislyak promised to “postpone the vote and to allow for consultations,” according to the transcript. Mr. Flynn responded: “OK. That’s good.”

The documents also revealed highly sensitive F.B.I. abilities, showing that the bureau was able to monitor the phone line of the Russian Embassy in Washington even before a call from Mr. Kislyak connected with Mr. Flynn’s voice mail.

In other words, the F.B.I. wiretap was able pick up what Russians officials were saying to each other — in this case, discussion of a hacking operation — when they apparently were unaware that the open phone line was already transmitting their voices.