Rejection means your return failed a quality control check with the IRS -- usually some piece of information on the return doesn't match the IRS's records. It might be the spelling of a name, a birthdate, social security number, or some claimed fact (like a dependent) conflicts with a previous tax return. Or, they can't verify your identity with the PIN code and AGI provided.
If you can't figure out the reason, print your return and mail it in. Some problems are simply not fixable by the taxpayer.
