It could be because your social security is not taxable. If your Modified Adjusted Gross income (MAGI) is below the base amount for your filing status ($32,000 for Married Filing Jointly or $25,000 for all others), your Social Security is not taxable. Once your MAGI exceeds the base amount for your filing status at least part of your Social Security income becomes taxable. For more information see the following TurboTax Help Article: Is my Social Security income taxable?
Did you enter your Social Security benefits as reported on the SSA-1099 in the correct section of the TurboTax program?
To enter Social Security benefits reported on form SSA-1099
Click on Federal Taxes (Personal using Home and Business)
Click on Wages and Income (Personal Income using Home and Business)
Click on I'll choose what I work on (if shown)
Scroll down to Retirement Plans and Social Security
On Social Security (SSA-1099, RRB-1099), click the start or update button
If you did, the SS income may not be taxable.
Up to 85% of Social Security Retirement/Disability/Survivors benefits becomes taxable when all your other income plus 1/2 your social security reaches:
You can check the SS benefits and the taxable amount, if any, on your federal tax return. Look at Form 1040 on line 6a for the SS benefits reported and on line 6b for the taxable amount of SS benefits, if any.
You can view your Form 1040 plus Schedules 1, 2 and 3 at any time using the online editions. Click on Tax Tools on the left side of the online program screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.