Is there a software mistake? Why am I unable to e-file this year, when I have in the past and my situation has not changed?

I am unable to e-file this year. I have e-filed every year in the past, and nothing has changed about my situation. Why must I file by mail this year?

I have lived abroad for several years, and I have always been able to file electronically via TurboTax.  I qualify for the Foreign earned income exclusion from Form 2555.  The software went through the same process, and I owe $0 in taxes.  This is the same situation as the past several years, and I was able to e-file easily.  

Has the IRS changed the rules for electronically filing?  Did Turbotax make a mistake?