Hi @Anonymous User
See if anything in this linked guide helps and if you are a Sky customer then have a read of the section about "Are you a Sky customer" (click the green arrow by the side of it to expand the on screen information).
https://help.nowtv.com/article/how-to-change-email-address
Apart from that maybe try a different internet browser with the ad blocking software disabled or a Private Window or Incognito mode when accessing your account to change your email address.
If no luck then click on the Get in Touch blue button on the RHS of the guide and contact live chat for further assistance & help.
