W-2 Box 12=D, $7,986.75; Box 13=Retirement Plan (Active military BRS) TurboTax says contribution max=$6,000 & I owe penalty. Max is actually $12,500. How to fix?

[VolvoGirl]

Do not enter it under Deductions & Credits.  That is only for IRA accounts.  You have an 401K account at work.  Only enter it from the W2 nowhere else.  

[dmertz]

And to be clear, a 401(k) is not an IRA.