I filed a 2021 tax return to claim my qualifying child. The IRS rejected my return because someone filed their 2021 return before me and claimed my qualifying child. I am eligible to claim my child for the Child Tax Credit, so what should I do

If you filed a 2021 tax return to claim your qualifying child and the IRS rejected your return because someone else filed their 2021 return before you and claimed your qualifying child, you should follow these steps to address the issue and claim the Child Tax Credit (CTC):

1. File a Paper Return: Since your electronic return was rejected, you need to file a paper return. Ensure that you include the name and Taxpayer Identification Number (TIN) of each dependent for whom you are claiming the CTC. Specifically, for each qualifying child under 17, you must enter the required Social Security Number (SSN) for the child in the Dependents section of your tax return and check the Child Tax Credit box.
2. Do Not Attach Additional Documentation Initially: When filing your paper return, do not attach any additional information or documents proving your eligibility to claim the dependent. The IRS will contact you by mail if they need any supporting documentation.
3. Respond to IRS Inquiries: The IRS will send you a letter inquiring about your child to determine who properly claimed them. If the other person who claimed your child hasn’t already corrected the SSN or filed an amended return to remove them, a letter will be sent to them as well. Be prepared to provide any necessary documentation to support your claim when requested by the IRS.
4. Identity Theft Considerations: If you suspect that the issue might be related to tax-related identity theft, you should take steps to protect yourself. Notify the IRS by filing a Form 14039, Identity Theft Affidavit, through IdentityTheft.gov or by filing the paper Form 14039. This will help the IRS to resolve any identity theft issues and ensure that your tax return is processed correctly.
5. Claiming the CTC: Ensure that you meet all the requirements for claiming the CTC. This includes filing Form 1040, 1040SR, or 1040NR and including the name and TIN of each dependent. If you are eligible to claim the child for the CTC, you should file your return claiming the child as a dependent and claiming the CTC.

By following these steps, you can address the issue of your rejected return and properly claim the Child Tax Credit for your qualifying child.

Sources:
Publication 1380
Instructions for Form 8862 (12/2023)
Publication 501 (2023)