Box 12 has a code of AA and DD.  The money showing for the AA was rolled over from the previous employer to a personal ROTH IRA, so how do I get rid of the retirement contribution credit showing up?

If the "AA" money was not new money contributed in 2016, then your payroll department should fix your W2.  If not, the IRS is going to believe that you're entitled to the credit.  The only other thing you can try is go to My Account (top menu), then Tools, then Delete a Form.  Try deleting form 8880.

Thank you for your help!

You're welcome.  Good luck!