I wanted to change the path of my URL for one of my site pages. I change tried the change the path by going to Pages > My Page > SEO (Google) and changing the URL from there. However, when I change the URL, it gives me the error "That URL's already taken, pick a fresh one!" It is not already taken and I'm not using it on any of my other pages. In fact, when you go to the URL, it says it cannot find it.
Here is the URL: https://www.hostendapp.com/support
Why is this happening and how can I fix this?