The most obvious reason is that the User could be making a typo when entering the eNotices Ref Number. Confirm this and in particular, if the number/code contains a Zero or the letter 'O', ensure this is entered correctly.
Verify that the User is entering the unique eNotice ref number and not the assessment number or property ID.
Have the notices from the submission been emailed yet? If they haven't, this could indicate that the data has not yet been made available to the eNotices database for verification. This is often the cause if registration is attempted from the proof samples. Please try again once the notices have been processed through the eNotices database.
Was this notice included in any Extraction with a "Do Not Print" or "Return Flat" rule? By default, these notices are not made available in eNotices and cannot be used to register an eNotices profile.
Forms Express presumes that if a notice is not to be issued to a ratepayer or customer by post, it should not be available by electronic means.
If you wish for future notices within an extraction to be made available in eNotices and therefore be used to register, please check the box within the Extraction area that states "Show in eNotices (for recipient)? ".
If none of the above reasons are applicable and especially if you are receiving a large number of invalid errors, please log a Support Ticket ASAP.
Please be sure to include details of specific notices coming up invalid (assessment/account number/s, name on notice, etc.)