Aw, shucks. You are doing it correctly, but for "some" users that is a known issue, and you seem to have been caught by that glitch. See this FAQ on this issue. It will also have a link where you can sign up for notifications:
FAQ: State E-file Error: "Your Transmission Didn't Go Through Due to Duplicate Social Security Number"
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https://ttlc.intuit.com/questions/4210149">https://ttlc.intuit.com/questions/4210149</a>
