Thank you for your prompt answer.
Again, I’d like you to tell me first you want to publish a page on my site even for a test. You can keep trying with that test page is you need.
This may work for external link, but it still doesn’t work for internal link. I did try again and I arrived on that 404 page with the url : https://www.webgeoservices.com/wp-admin/_wp_link_placeholder