My IL return got rejected for the code ILHEADER-8500-3, regarding the primary taxpayer's SSN.

This code explains that "the Primary 'TaxpayerSSN' must not duplicate the Primary 'TaxpayerSSN' of any previously accepted return for the current tax year."

My wife and I are filing jointly. My wife has already filed her tax return. I assume this rejection code is related to the fact that she already filed. 

Does this mean I'll have to file by mail? Thank you!