The IRS - not eFile.com - has rejected your return and you are required to make a correction, because the spouse's SSN has been used on another tax return this year.
Solution: Please sign in to your eFile.com account now and click on My Return in the upper left and review the IRS message on the right.
1. Sign in: https://mytaxes.efile.com/1040/SignIn/
2. Click on Name & Address and the left and verify the SSN on the right side. If it's incorrect, please update it and re-efile your tax return(s) without a new charge.
If all SSNs are correct, then you need to print and mail your return. Please go to your My Account and download, print, sign and mail in your returns. Otherwise make correction and re-eFile at no charge.
Here are the mailing addresses: https://www.efile.com/irs-mailing-addresses/
If you have questions, please contact us as soon as possible so we can assist you with your Tax Return.