[SOLVED] pdfmake error

Hello
in "Client Before" custom button I've these lines of code:

ajax.addPDF( 'pdf', {}, function() {
		return ctrl.dialog( {
			title: 'Send via email',
			fields: [{
				name: 'email',
				value: ''
			},
			{
				name: 'filename',
				value: 'attestazione-' + proxy['IDF'] + '.pdf'
			}],
			ok: 'Send',
			cancel: 'Cancel'
		});
	});
return false;

But when I click the button I get this error (in browser console):

pdfmake.min.js?36714:2 Uncaught Error: Unrecognized document structure: {"ol":"","style":["html-ol"]}
    at t.e.preprocessNode (pdfmake.min.js?36714:2)
    at t.e.preprocessVerticalContainer (pdfmake.min.js?36714:2)
    at t.e.preprocessNode (pdfmake.min.js?36714:2)
    at t.e.preprocessVerticalContainer (pdfmake.min.js?36714:2)
    at t.e.preprocessNode (pdfmake.min.js?36714:2)
    at t.e.preprocessTable (pdfmake.min.js?36714:2)
    at t.e.preprocessNode (pdfmake.min.js?36714:2)
    at t.e.preprocessVerticalContainer (pdfmake.min.js?36714:2)
    at t.e.preprocessNode (pdfmake.min.js?36714:2)
    at t.e.preprocessDocument (pdfmake.min.js?36714:2)

Please, anyone know how to solve or fix this error? I'm using php 10.5 b. 36714 (and I'm sure that the same code with the 10.4 version was working good)

Many thanks in advance.