> There's no impact by a failing e-filing system.

Unless you efile after the post office closes on the night of the 18th and/or don't own a printer and/or can't get there after efile fails but before the post office closes.

Or there are people like me, where my efile was rejected on April 19th. Now what do I do? If I try to efile again, it just says, "sorry, you're past the deadline". If I mail in a form it will technically be late, although I guess if they say anything I can show them my failed efile attempt...