Are you married? Excess Social Security can happen when you are married and assign both spouse's W2 to the same person, it will look like all the W2s belong to only 1 person and too much social security tax was paid for that 1 person. You need to check 1040 line 71 for it. And by assigning both W2s to the same person the program wouldn't know a W2 is missing from the spouse. It just would think they are both for you.
For 2014 the max SS is $7,254 per person.
So if you (either one spouse, but not both together) had more than one employer and the total of box 4 on all the W2s ( for Social Security is more than the max (for each person) you get the excess back on your tax return. But not if both spouse's W2s went over.
OR It could be the case that you entered a code wrong for a Box 12 amount on your W-2. If you used code A instead of the correct code, that error may also have produced excess social security.
If you used the Online version you would need to download the .tax file from online to open in the Desktop program. If you look at your W-2 s in the Desktop program, in Form mode, you'll see a line at the very top where the box is checked to show who you chose as the owner of the W-2. That's where the mistake lies. If you choose the wrong person last year it will transfer and will continue to be wrong.
For 2014, You can use this FAQ on how to amend 2014 to get the program and your data file
https://ttlc.intuit.com/questions/2693844-how-do-i-amend-my-2014-turbotax-online-return Did you file 2015? Better check line 71 and see if it transferred over wrong and happened again. You might be getting a bill for 2015. And for 2016 either don't transfer from 2015 or delete and re-enter all the W2s carefully next year to stop it from continuing. Pay attention to which spouse you assign the W2.
ps.... See this post about 2014. The user found that the box for spouse was NOT checked.
https://ttlc.intuit.com/questions/3399398-box-71-issue-with-an-irs-notice
