When you set up or change your email address you will receive a test email message containing a confirmation code that allows you to activate your email address for the specified message type.
Please note: If you do not activate your email address, HM Revenue & Customs (HMRC) will be unable to send messages to you.
When you receive the test email message containing the confirmation code you have three attempts at entering the code. If the code is incorrect at the third attempt you need to request a new code by clicking the 'Send new code' button. For security reasons HMRC will only issue one code per 24 hour period.