The taxes have been rejected because it says the SSN of my spouse is duplicated but we did not file this year yet. What should we do to fix this?

[xmasbaby0]

If you have made certain that her SSN is entered correctly and your return is being rejected for a duplicate SSN, then all you can do is print, sign and mail the return.  Once a SSN is in the IRS system as having been used on a 2018 tax return, any other return using that SSN will be rejected.  it is possible that someone else mis-typed their SSN and caused this.  (Or it could be an identity issue--the IRS will sort it out)

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.