Are you sure that no one else has prepared a return for you in the past? ex: a parent, an accountant?

To change your answer to the question, go to the Tax Home ⌂ page, click on “Tax profile” & then “Mandatory Questions”. The question “Is this your first tax return being filed with the CRA?” is the 1st one on the page.

Yes, I just came in Canada so none could file a tax return for me.

@jcl06   That error code is from CRA. If you are filing for the first time, you might have to print & mail your return to CRA. CRA will not accept an electronic filing if they do not have anything for you on their record.