This is because the administration is lying.
Despite insistence that widespread voter fraud exists and pledges to investigate the matter fully, it seems the Trump administration has not bothered to contact top state election officials across the country.
The Huffington Post asked all 50 secretaries of state and election officials in the District of Columbia if they had been contacted by the White House or Department of Justice regarding the forthcoming investigation. Not a single secretary of state’s office responded to say that it had.
There's not going to be an investigation. They're going to contact nobody. At the very most, if White House strategists are feeling extremely pressured and need to release something in order to "prove" to the press that they haven't been lying through their teeth about every aspect of Donald Trump's feverish conspiracy theory, they will release a half-assed, unsourced "report" put together by White House interns referencing Alex Jones or Breitbart or some tinfoil-hatted idiot you've never heard of as their "evidence" of a kabillion illegal invisible voters from Neptune.
Maybe they’ll have Sean Spicer do a 20-minute song and dance number about how their report now should be taken as more authoritative than all 50 secretaries of state, all research, all investigative reporting, all government probes and every fracking other thing besides, and that will be the end of it.
Donald Trump was clearly lying when he said their were millions of illegal votes. Everybody knows he was lying. The White House knows he's lying. Mike Pence, Jason Chaffetz, Sean Spicer, and every other last person knows he's lying, and the entire Republican charade from that first day until this one has been an exercise in pretending that the sitting Republican president is not, in fact, either a pathological liar or mentally ill.