Hi @milena.perraud, that is strange. I was able to create a hidden test album and publish photos to it using http://www.milenaperraudphotography.com/backlight/?m=publisher. I’ve since deleted the album.
If this still isn’t working for you, can you please email me the file ttg.log that should be found in the Documents/LrClassicLogs directory on your computer? The file may be very large, so I suggest zipping it first. I’ve sent you a message with my email address.