I don’t quite understand what you’re talking about. Your link does not point to any website and would rather go to a backend where we do not have access and do not want to have access.
My guess is that you want to store an email as a link target for a menu item in a menu defined in your backend. My recommendation in this case would be to use “mailto:” as a prefix for the link target, e.g. mailto:info@example.com.
If this is not the case, you are welcome to show a screenshot of what you are doing. You can upload a screenshot as described here: https://wordpress.org/support/forum-user-guide/block-editor/#adding-screenshots
