Do you mean that you received reject code SEIC-F1040-506-02? Please clarify.
Rejection SEIC-F1040-506-02 means that on Schedule EIC, the qualifying child's social security number (Line 2) cannot be used more than once in a tax return or on another return. This occurs when you try to claim the Earned Income Credit (EIC) for a child on your return, but someone else has already claimed the EIC for that child on a different return.
What error message are you receiving when you attempt to login?
Since you received your stimulus payments, if you have e-filed your 2020 Federal tax return and the tax return is rejected by the IRS, you will have to correct:
See also this TurboTax Help.