Hi!

Sometimes you will experience an error when you're attempting to use an email address that is already attached to another Path of Exile account. It's only possible for an email to be used on one Path of Exile account at a time, which causes an error when you attempt to complete adding it to another!
Please try using an email address that is not already attached to an account and it should complete successfully. :)
If you have any further troubles making the change please contact us at [email protected] and we can check into that for you!