why is my child not a dependent?

You can claim a children as long as they meet the following requirements:

Qualifying child:

• They're related to you.
• They aren't claimed as a dependent by someone else.
• They're a US citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They're under the age of 19 (or 24 for full-time students).
• There's no age limit for permanently and totally disabled children.
• They lived with you for more than half the year (exceptions apply).
• They didn't provide more than half of their own support for the year.

Or Qualifying relative:

• They don't have to be related to you (despite the name).
• They aren't claimed as a dependent by someone else.
• They're a US citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They lived with you the entire year (exceptions apply).
• They made less than $5,050 in 2024.
• You provided more than half of their financial support.

Revisit the Personal Info section scroll down to Dependent and click Edit. Make sure you are answering all questions correctly. Make sure that you didn't check that your child’s SSN is not valid for employment.