I e-filed Federal 1120 with no problem. It navigated me to the 8453-C form, which I printed out, signed, scanned, and submitted a pdf of it.
But after completing the California Form 100 and clicking to e-file, it took me directly to the final stage of ready to file, this can't be reversed. But it never asked me to print scan and submit a California efile return authorization for corps - 8453-C
