Wordpress - Stop Wordpress appending `-2` to the end of my url after i change it

I know this topic is old, but I was having the same issue, and none of the suggested fixes worked.

I didn't have any pages still in trash. I didn't have a category with the same name as my page. I didn't have another page with the same name. So I did something crazy. WP was trying to name my page as page-2, so I went to mywebsite.com/page to see what happened.

A page with a single photo popped up. I had a PHOTO with the same name as the page, and WP media manager gives photos permalinks based on the file name! Fix was to rename the photo (still keeping SEO in mind), and using the permalink editor for the page. TAH DAH! Like magic, it worked