I finally got my stepson’s SSN this past summer and tried to claim him on my taxes but was told he didn’t qualify! Why?

[flabadap]

Why didn’t turbo tax ask for his SSN?

[xmasbaby0]

There must be more to the story.    What do you mean by "finally got my stepson's SSN...?"    Was his SSN recently issued?   Is he a newborn?   What was the issue with the SSN?   

[flabadap]

Sorry for the long delay!

ok, my stepson is my wife’s son from a former marriage. He lives with us and I’ve been supporting him for the last 6 years. I tried getting a TIN but it never came. At the time it was the beginning of the COVID hysteria. I was told that lack of personnel and closures were the problem. 
last year I started receiving SS benefits and for his benefits he had to have a SSN. We got his SSN but turbo tax doesn’t even ask for it. Just says he’s disqualified. One possible reason is because he still goes by his biological father’s last name, but I never saw information stating that as the reason.

[xmasbaby0]

If he is entered in MY INFO already and is not being recognized as a dependent, delete his name and start over by re-entering the child.   When you enter his name in MY INFO use the name that matches the child's current Social Security card.  You will be asked for his SSN in MY INFO.   Make sure you say he lived with you all year.   Be very careful with the question that asks if the SS card is marked not valid for employment---You do not want to check that box.  Say NO to that one.    When it asks if he paid for over half his own support say NO to that.