www.wysiwygwebbuilder.com

Hi,

That's what I was just told by my hosting technical support: "The issue is that the website's pages do not redirect visitors to the URL that includes the file extensions. In this case, it can be fixed only by updating the URL structure of your website."
I asked for the .htaccess rules related to the file extensions to be removed because Facebook says "URL returned a bad HTTP response code."

Now, it's not working, it's showing error 404. I have NO idea what to do

.htaccess is not related to WWB. It's server configuration.

You can remove file extensions from internal link via: Tools -> Options -> Publish -> Hide file extension for internal links
Please read the warnings about this in the help before enabling this option! This is for advanced users.

I believe that this is related to the following. Link shortening See my reply on using Hide file extensions. As Pablos reply this feature is for "Advanced" users and should be used with caution if you are unsure of its use.

Thank you both. I forgot I ticked the box.