Is the error with a social security Number on your return for you or a dependent? Or with the amount of your SS?
Do you have an amount on 1040 line 6b or is it 0? What usually happens is the IRS changed some other income on your return. Like the taxable amount of a 1099R you got or you missed entering some income. Like if a 1099R got entered on the wrong line 1040 line 4 or 5, the IRS would miss it and think you didn’t report it. By increasing your other income it made more of your SS taxable.
You get 0 on 6b if you didn't answer the Foreign question right. Or if the amount on 6b is too low and you are married you answered it wrong for one spouse.
There is a new question this year asking if you lived in a foreign place. People have been answering it wrong or skipping it. Go back through the Social Security entries and check, check for each spouse if married. If the IRS adjusted your return you do not need to amend.
