I am trying to e-file Form 7004 for Form 1041 without an expected balance due and I get the error message that without a balance due the Form 7004 must be paper filed.  Why is this?  I have e-filed it many times before with no balance due without difficulty.   I can't find anything from the IRS stating that Form 7004 can't be e-filed without a balance due but could have missed it, and the instructions for the Form list no such requirement.  Paper filing the extension incurs the additional cost of certified mail that I would like to avoid.