I already have nat Geo account connected to my email address, so I cannot create a new account. When I try to login with my existing account I get the following screen from the website and the app. Don't know about the EU bit as I created the account in Australia.
Sorry, we couldn't log you in
You are attempting to login to our US app from an EU account. This app is not available for users in the EU at this time.
How long has it been since you last logged in?
Please try the steps advised in this blog.
Let us know how you go.