Check Box 3 and box 4 on your W-2 input to make sure the amounts entered are correct. Employers had the option to defer the employee share of social social security by orders sign near the end of 2020. The social security tax withheld in box 4 should be 6.2% of the social security wage amount in box 3. If those amounts are correct, you can continue through the warning and complete your return.
If you had only one employer during 2020 and your Form W-2c, Corrected Wages and Tax Statement, for 2020 only shows a correction to box 4 (or to box 14 for employees who pay RRTA tax) to account for employee Social Security (or Tier 1 RRTA tax) that was deferred in 2020 and withheld in 2021 pursuant to Notice 2020-65, no further steps are required. However, if you had two or more employers in 2020 and your Form W-2c for 2020 shows a correction to box 4 (or to box 14 for employees who pay RRTA tax) to account for employee Social Security (or Tier 1 RRTA tax) that was deferred in 2020 and withheld in 2021, you should use the amount of Social Security tax (or Tier 1 RRTA tax) withheld reported on the Form W-2c to determine whether you had excess Social Security tax (or Tier 1 RRTA tax) on wages (or compensation) paid in 2020.
