To Add.
For the problematic return....under 'NetFile'.. upon clicking on 'file rejection' .... states the following:
Rejected
Result:16
The Canada Revenue Agency's records indicate that your 2020 tax return was already received ---------->Contradictory
The federal income tax return is ineligible for NETFILE.
Please verify, under the Tax Return tab, whether the federal return is required for filing and, if so, rectify accordingly:
The error and warning messages at the bottom of the page.
The error and warning messages within the Review tab under the category Messages.
If we then navigate to 'Review' ... -> important messages
Electronic filing errors
"You have to confirm that your spouse's adjusted taxable income is NIL.
You have to confirm that your spouse's provincial/territorial adjusted taxable income is NIL.
... and ANOTHER CONTRADICTORY statement under 'maxback analysis'
"T his federal return has been transmitted and accepted." (for both parties)...