Trump didn't lie. Find his words in context and see that he was questioning, or that he was quoting others who supposedly were knowledgeable.
What happened to all that? It didn't go away. It's still there. Total dishonesty of election officials in front of the general populace. If not illegal, it was because they had the authority to make unconscionable laws.

Trump to the Georgia Sec of State (the guy in charge of elections), one day after Trump received the report on the investigation he paid for that determined there were no irregularities involving dead people or duplicate votes:
“So dead people voted, and I think the number is close to 5,000 people. And they went to obituaries. They went to all sorts of methods to come up with an accurate number, and a minimum is close to about 5,000 voters.”
“But you also have a substantial numbers [sic] of people, thousands and thousands who went to the voting place on November 3, were told they couldn’t vote, were told they couldn’t vote because a ballot had been put on their name.”
Here he is repeating Rudys lies about Ruby Freeman and her mother. This was after he asked Bill Barr to look into it, who did, and testified under oath that he personally told Trump that they were doing there job exactly as they should have been. No suitcases, no trunks, just transporting ballots in bins from one area to another the same as any other polling facility.
“We had at least 18,000 . . . voters having to do with her. She’s a vote scammer, a professional vote scammer and hustler.”
“They weren’t in an official voter box, but they were in what looked to be suitcases or trunks, suitcases but they weren’t in voter boxes.”
There's plenty more, let me know if I should keep going.