Look at the actual SS card, the LAST name will be shown on the second line of the name (first and middle will be on the first line, last name below that). That's the name you want to use as LAST. First & Middle names aren't cross matched.
Day my child's name is Vanessa corn bread Jones John .....how do I put it two middle two last Vanessa ,corn,bread at the top. Jones ,John at the bottom I've been having trouble
The top line of the SS card shows the first name (IRS doesn't cross match this line)
The bottom line shows the last name.
As long as you have the name on the bottom line of the SS card entered as the Last name on the tax return, it should get accepted.