User Profile Page Issue

I have a problem with the user page.

It looks broken and I’m getting a message ‘You are already registered’

It looks like this:
https://www.dropbox.com/s/mkqozv4nbenf9jz/Screenshot%202018-12-17%2018.16.42.png?dl=0

With all plugins deactivated, still the same issue:
https://www.dropbox.com/s/qr5hqixupr9kvsw/Screenshot%202018-12-17%2018.11.59.png?dl=0

Installed on the test site and it looks like this:
https://www.dropbox.com/s/x1cbi6bilbgaa31/Screenshot%202018-12-17%2017.38.18.png?dl=0

Do you have any idea what could be doing this or how to address, please?

Thanks

The page I need help with: [log in to see the link]