How do I figure out why my extension was rejected?

I got this error:

R0000-902-01 - Taxpayer TIN in the Return Header must not be the same as a TIN of a previously accepted electronic return for the return type and tax period indicated in the tax return.

I already confirmed that my and my spouse's social security numbers are correct, and neither of us has filed yet, so why is this happening? Fraud?

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