I created a website and upgraded to premium before publishing. I am still getting "Created on EditorX" banner on some pages. How to avoid?

Do you have a link? It could be a cached version of the site that you are viewing. I would suggest clearing your cache and trying again. If you still have this issue, you should reach out to support- Editor X: Contacting Customer Care for Support | Help Center | Wix.com

I always thought you had to have domain name associated with the account to remove the . Did @wrexe suggestion work?