How close was Austria-Hungary from signing a separate peace with the allies in 1917?

Based on the 1919 publication called "Documents and States Relating to Peace Proposals and War Aims: December 1916-November 1918" Emperor Karl of Austria was very serious about negotiating a separate peace with France. On January 11 1917, A-H sent a note to the major neutral states pleading their case for fighting a war. It was particularly aimed at the U.S. whom they thought would be a mediator in a peace negotiations. Throughout 1917, the Austrian Foreign Minister Count Nikolaus Revertera approached the French representative in Switzerland Major Armand. Talks became serious in April of 1918 whenCount Nikolaus Revertera issued a letter to a agent of Clemenceau in Switzerland. In the letter, he required that negotiations could only begin if France renounced its claims on Alsace-Lorraine; a proposal that they rejected. In the April meetings, Count Revertera gave the French the impression that any plans created for peace would also be accepted by Germany. These talks led nowhere since Clemenceau did not take the Austrians seriously, especially after Count Czerin's lied about a damning letter between Emperor Karl and his brother-in-law