Have you reviewed your W2 worksheet entries ?   

are their withholdings oddly higher than whats normally seen for that state? 

I feel like some states may have a limit, like the withholdings can only be XX% of the wages in order to EFile, I think its to weed out fake W2s with extra high withholdings.

Indiana is one of those states that has a 50% limit. 

Also, Indiana will not efile if there are other withholdings of same amount.... ie   federal is $123 and Indiana is $123