Retirement tax questions

There is no error for that in Turbo Tax.  

Are you married and filed Joint?  And you both had W2s?  The IRS is probably right.  They usually are in this case.  You assigned both spouse's W2 to the same person so it looked like that person went over the max.

For 2018.  Do you still have copies of all the W2s?  Look at box 4.  Did either of you have more than 1 employer?  You only get excess SS back if one person had more than 1 employer and those employers took out more than the max of  $7,960.80.  So add up your W2 box 4.  Is it more?  Then add up your spouse's W2 box 4.  Is their box 4 more than $7,960.80?