Here're things you can try if you cannot authenticate.
Are you using a cellular mobile phone number? If not, please retry using it. You cannot authenticate using landline phone numbers.
Please clear your browser cache and retry to authenticate your mobile number on the profile page.
When you enter your mobile number, please enter the country code first without the leading zero and special (+ - , .) characters.
Is your country on this list? If not, it’s not currently supported. https://help.xank.app/en/articles/4488351-supported-countries