My children have just received their SSN. I filed federal return 2018 using their SSN for the first time. Online filing was rejected twice. What should I do?

[DDollar]

When the IRS rejects your tax return because social security numbers on your return don't match their data base, you only option is to print your returns and mail them.  You may want to wait few days, or even file an extension and contact the Social Security Administration about the problem, but other than that, your only option is to print and mail.