When the opposition Coalition decided to oppose the proposal, it was lost. No referendum to change the Constitution has ever succeeded if the opposition opposes it.
The Coalition of 2 conservative parties is often referred to as the Noalition. Fact checkers have listed the lies told by opponents of the proposal, but in the post-trumpian world, lies are so easily believed. And racism definitely played a part.

The brutal truth of the referendum result was that Yes campaign couldn’t cut through to a hesitant electorate analysis by Laura Tingle
(Laura Tingle is the chief political correspondent for nightly current affairs program 7.30. One of Australia's best journalists and top political analysts, she's spent most of her 35-year career in journalism reporting on Australian federal politics, and the country's major policy debates. A journalist, author and essayist, she was formerly the political editor of The Australian Financial Review.)

Northern Territory records No vote on Voice to Parliament, despite remote communities favouring Yes

Voice Referendum Live Results and Updates   Postal votes have yet to be counted

analysis The Voice to Parliament was an idea decades in the making. In mere hours, it was shattered ... In the immediate days that follow, there will be silence. Silence from Indigenous leaders who have entered a period of grieving.
There's no shortage of irony in the fact that after weeks — years — of white voices being some of the loudest and most toxic, they will again be the loudest in the aftermath. Especially with parliament returning for a sitting week only 48 hours later.
... The federal government will be preparing for a difficult week of questions over what happens next, now that the Voice to Parliament has been rejected at a referendum.
Nations leaders who've for years carried the weight on their shoulders, who faced racist attacks during the campaign, only to see their years of work be dismissed overnight.
Thomas Mayo, who said he was devastated, told the ABC that history would look poorly on opposition leader Peter Dutton and the No campaigners, who he accused of lying to the Australian people.
Academic Marcia Langton went further and dubbed reconciliation "dead", warned that it would be at least two decades before Australians were "capable of putting their colonial hatred behind them and acknowledging that we exist" and accused No campaigners of "poisoning" Australians against the Voice.

... There was no hiding the smiles on Peter Dutton and shadow Indigenous Australians spokeswoman Jacinta Nampijinpa Price's faces last night. In the world of Realpolitik, they are coming out on top
... In the meantime, the focus will shift to Dutton and how genuine he was in vowing to deliver "practical" outcomes to close the gap. His early comments last night shred the little hope there might have been for bi-partisanship.
He wants a royal commission into allegations of child sexual abuse in Indigenous communities and an audit of spending programs (many of which likely started under the Coalition, and yet this doesn't seem to rate a mention) ...

video of Straight From the Heart (the Makarrata Song) - Tripple Effect with Thomas Mayor