Is this the first time you are filing a return with the CRA? Do you have any locked forms from this list on your return? https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/tax-return/turbotax-say-forms-locked-finalized/L9h4thZZJ_CA_en_CA
If not, then make sure to check your personal information, like your name & address. Make sure the information matches what the CRA has for you. If you are not sure what they have on file for you, you can confirm it with them.
Also make sure that you have not said yes to the question, "Is this your first tax return being filed with the CRA?" under "Mandatory questions."
If you have a NAC (Netfile access code), we recommend removing it and giving it a try because it is not a required field.
Let us know how it goes.
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