AGI and PIN are correct. Why does efiled return still get rejected by IRS?

I have tried the "enter 0 for AGI" as suggested by Turbo Tax rep.  Still rejected.  I requested the IRS transcripts to verify AGI.  AGI figure was the same as reported... returns still rejected saying "AGI and/or PIN" is incorrect".  PIN is the same as last year and the year before!!  Still rejected.  Called Turbo Tax.  Spoke with a rep at TT.  She didn't know what she was talking about.  I asked to be referred to a supervisor.  She said they would call... never got a call.  Got an email saying that she "Casey" had resolved my issue.... returns still rejected.   What is the problem???

Is my only alternative to print and mail returns?