Why am I getting an error message when trying to register for the will writing service?

Why am I getting an error message when trying to register for the will writing service?

In experience this is simply the format of your address on your account. 
Please click update details and re-enter your address. This should resolve the issue you are experiencing. 
For any reason it doesn't. Please select to speak to an operative on live chat who will be able to assist. 

Kind regards. 
HH.