If you were living common-law then separated, this means you are now separated and not single.
As per the Canada Revenue Agency (CRA)-"Separated means that you have been living apart from your spouse or common-law partner because of a breakdown in the relationship for a period of at least 90 days." "Single means that none of the other marital statuses applies to you."
If this is the case, you will need to contact the CRA to confirm/correct your marital status with them before being able to Netfile.
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