More information may help resolve your issue. For example, did you include your full salary before the 401(k) contribution made by you as an employee as a deduction on your Form 1120S tax return? Did you report the 401(k) contribution you made in box 12 of your W-2 from the S Corp?
As a shareholder, your S Corp isn't allowed to contribute to your 401(k). Instead, the contribution to the 401(k) must be made from your W-2 wages paid by the S Corp.
See the IRS website at this link for Retirement Plan FAQs for S Corps.
More information may help resolve your issue. For example, did you include your full salary before the 401(k) contribution made by you as an employee as a deduction on your Form 1120S tax return? Did you report the 401(k) contribution you made in box 12 of your W-2 from the S Corp?
As a shareholder, your S Corp isn't allowed to contribute to your 401(k). Instead, the contribution to the 401(k) must be made from your W-2 wages paid by the S Corp.
See the IRS website at this link for Retirement Plan FAQs for S Corps.
If you are "truly" an employee of your S-Corp (and you most certainly can be) then that means the S-Corp issued you a W-2. Therefore, your 401(k) contributions should be in box 12 with a code "D" indicated. If so, that amount in box 12 is not included in box 1 of the W-2.