My last name is to long, what do I do?

[SidneyP]

 You can fix that by removing the last letters that don't fit.  The IRS matches the social security number with only the first few letters of the last name.

[isabelagob]

I`ve tried several times and it doesnt work :(

[SidneyP]

Just enter the first 20 characters and be certain that your Social Security number is correct on your tax return

[felipesoares79]

Same thing for me. I end up filling by mail because it fails every time.

[Critter-3]

The total characters allowed are limited for the entire name ... so reducing your first name to an initial and deleting the middle name usually works.  I do believe the total allowed is 35.