See if this post helps for which ssn was rejected
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IND-517-01 - A Dependent SSN in the return must not be the same as the Primary or Spouse SSN on another return where 'PrimaryClaimAsDependentInd' or 'SpouseClaimAsDependentInd' is not checked.
The rejection code IND-517 is used when a dependent's social security number has been claimed on another return as a taxpayer or spouse. Often this happens when a dependent files their own return and does not indicate that someone else can claim them as a dependent.
To determine which of your Dependents was already claimed, you will need to look at your full Reject Code. The last two digits of the Reject Code tells you which Dependent it was based on the order they are listed on your Form 1040.
For example, Reject Code:
If you need additional assistance in figuring out which of your Dependents was claimed, please comment below
My code reads IND-507. I CLAIMED 2 CHILDREN AND ONE ADULT. HOW DO I KNOW WHO WAS ALREADY USED
To determine which of your Dependents was already claimed, you will need to look at your full Reject Code. The last two digits of the Reject Code tell you which Dependent it was based on the order they are listed on your Form 1040.
For example, Reject Code:
This TurboTax help article defines a dependent.
Here is a link about what to do if someone has claimed your dependent.
It don’t have a number after it to see what dependent might been claimed
This reject frequently occurs when the dependent's SSN on this tax return was present as a dependent on another tax return, or the dependent already filed a return without indicating they would be claimed as a dependent on another return.
Try These Steps.
1. Verify the dependent's Social Security Number (SSN) matches his or her Social Security Card.
2. Verify the SSN is not the same as the taxpayer's, spouse's, or other dependent's SSN.
3. Verify the SSN is unique to this tax return and is not used on any other tax return. If the SSN is not correct or unique, correct the dependent's SSN and resubmit the return electronically. If the SSN is correct and unique to this tax return, you cannot e-file the tax return for the current tax year. You must print and file the return by mail.