Her trip to Salzburg did not help her.
Speaking to the media in Salzburg yesterday, French President Emmanuel Macron said the staunch Brexit backers had deceived the British people, promising them a windfall of funds and a painless exit.
Brexit was pushed by those "who predicted easy solutions", Macron said. "Those people are liars. They left the next day so they didn't have to manage it."
May had warned European leaders her plan - agreed to by her divided Cabinet in July at the Prime Minister's official country manor, Chequers - was the only way forward.
But Macron countered, "The Chequers plan cannot be take-it-or-leave-it."
European Council president Donald Tusk said May's signal proposal to create a British-European free-trade regime covering agriculture and goods - but not services - was not acceptable.
"There are positive elements in the Chequers proposal, but the suggested framework for economic co-operation will not work, not least because it risks undermining the single market," Tusk said.
The EU's single market offers much to its members but also requires the free movement of people among its countries. Britain wants to controls its own immigration and make its own independent trade deals.
Tusk said May has just four weeks to amend her plan or perhaps face the dreaded prospect of leaving Europe with no deal - a so-called doomsday scenario.
German Chancellor Angela Merkel warned, "There is still a lot of work to do on the question of how future trade relations will look."
Speaking of May's proposals, Merkel said, "You can't belong to the single market if you are not part of the single market, but you can develop a lot of creativity to find practical, good, close solutions."
Answering her critics at the meeting in Austria, May told the media, "If there is no agreement on a deal that is acceptable to the United Kingdom, then we're preparing for no deal."