Please review your NETFILE eligibility here: https://www.canada.ca/en/revenue-agency/services/e-services/e-services-individuals/netfile-overview/...
Also, if you entered a NETFILE Access Code (NAC), please double check that it is correct and has all 8 characters. You can also try submitting your return without the NAC. The NAC is optional and not required to file your return.
