CTC Tax Filing Issue: Error Claiming Son as Dependent in NJ Joint Return

I'm encountering an issue while filing taxes jointly with my spouse in New Jersey. We are trying to claim my 15-year-old son as a dependent for the first time, as he has been living with me for the past 11 months and I am the primary custodial parent. However, when submitting the tax return, I receive an error message stating 'Nondependent - for EIC/dependent care only'. This is puzzling, especially since our joint income is below $150,000. I've attempted to resolve this by deleting and re-entering his information, but the error continues.

Additionally, it's worth noting that my son and I have different last names, but my name is on his birth certificate, which is associated with his Social Security number. Could someone assist me in understanding why I am receiving this error and advise on how to rectify it?