First check the form to make sure it doesn't say "Do not file" on the top.
I know @maglib and @rjs used to do NJ tax returns, maybe they can check their 2021 software to see if it's a problem on theirs too, or whether a state software update is necessary and might fix it.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
