My Employer didn't mention about any notice he received.
I checked in the https://www.ssa.gov/myaccount/
I see my earnings are not reported. It is 0$ for the 3 years(2019,2020,2021) I worked with this employer. My tax return didn't have a problem on 2019 and 2020. For 2021 I got this notice.
Thanks for the info. This is the first time I am cross checking in SSA site.
What should be my next action?
