Hi @sterndata ,
Thanks for your answer, I installed Itheme and Wordfence, I logged out from all device and changed the password of the only user (me).
When you write “Check that post in HTML mode and remove the line.”
this sounds easy, but I actually don’t really now how to do it, there are no ‘post’ but only ‘pages’ in this website and I built the pages using elementor, I don’t know how to access to the HTML mode in elementor.
Thanks !