The wifi kettle will fail any set up where an incorrect password has been entered. You will be shown a page that allows you to start the setup process again. Choose that option and proceed as normal, ensuring to enter password carefully!
Please do not hesitate to get in touch with Smarter Support by emailing us at firstname.lastname@example.org. You can also give us a call us on 0800 802 1237 if you are in the UK or EU or on +1 (855) 489 5522 if you are in the US.