TT not permitting IRA contribution, stating I was covered by 401K. This is incorrect, as I received severance and was ineligible for 401K. How do I correct TT?

The W-2 you got for the severance has Retirement marked.  You need to see if the employer would give you a new one without it marked.

Otherwise no deduction

Thank you Michael.  I was able to find and correct the error.  The W-2 my former employer sent me did not have the retirement plan box checked, so I unchecked the box in TT and the IRA deduction was applied.  Thanks again.

Great news, I am going to post a very brief answer below just so others know this is taken care of.

Make sure the W-2 for the retirement is entered as you got it, and if the retirement box is not marked such as your case you are good to go.