When processing W-2s, a user may receive the following exception: Box 3 (social security wages) + Box 7 (social security tips) is equal to the Social Security wage limit for a prior year - with the only option being go back and correct.
Aatrix is recognizing $118,500 as a prior year's limit which is true, that was the 2016 limit.
The 2017 limit was increased to $127,200 for 2017: https://www.journalofaccountancy.com/news/2016/oct/social-security-wage-base-2017-201615372.html.
The employee should have continued to be taxed up to the 2017 limit because those wages beyond 118,500.00 are still taxable.
Create a Historic entry to correct box 3 (and 4 if necessary) using the steps in the W-2 wizard: