Error N1 usually means your identifying information doesn't match what the CRA expects.

1. Check your first and last name, date of birth, and social insurance number against your SIN documentation.
2. Confirm the answer to your first-time filer question. If anyone has ever filed a return on your behalf you are not a first-time filer.
3. Sometimes (very rarely), error N1 comes back when your tax return has already been filed for the year.

If all the details are correct and you haven't filed your return yet, you will need to contact the CRA before trying again. Repeated unsuccessful attempts (usually five) can lock your access to NETFILE.

Unfortunately, the CRA does not send us any more detailed information about why your particular return was rejected so we aren't able to help.