In our continuing efforts to strengthen protections against identity theft refund fraud, the IRS made some modifications to the way tax returns are processed through Modernized e-File (MeF) beginning with the 2016 tax season. MeF is rejecting returns based on characteristics that have been deemed highly suspicious. In order to protect taxpayers, returns will reject with Business Rules IND-664, IND-665, IND-666, IND-667 or IND-672. This applies only to electronically filed (e-file) 1040 family tax returns. If you believe that your return was rejected in error, you may still file the return on paper. For your protection, you must either have a tax professional file your return or submit a paper filed return.