Maybe it was too wet for the leaf. Try rooting in regular, light AV soil with the ratio of one part peat, one part perlite (fine) and one part vermiculite. That works for me. I've done it in vermiculite as well, but I had oodles of holes in the bottom of a salad container, moist not dripping vermiculite and a top on the container. Some have rotted, others have thrived when I've done 100% vermiculite. Maybe you need more heat and sun?

thanks
any other advices?

Be sure you have a firm healthy leaf , the stem all the way down should be firm, no soft places. You can use rooting hormone if you wish, cover with a bag or cling wrap be sure it gets good light. I prefer to use artificial especially on starting leaves. When you cut the stem at 45angle make sure its short 1/2 to 3/4 inch, no more than that. After two weeks remove the cover but keep it moist , after 6-8 wks you should see signs of new life. Some have had good luck with just vermiculite. I use the combo , peat , perlite, verm.

Thank for all of you!