Always file paper.
When I was a kid, you filed taxes with a punch card included with a paper return.
My dad used to get a razor blade and slice an imperceptible slice off the end of the card.
My 2016 returns was by paper. My accountant, believe it or not, was offline (his wifi sucks) and he apologized for being offline with EFILE. He made copies for me and paid for Priority Mail on the spot. .