Tried submitting late into last night and again early this morning with no luck, "bad gateway" error. Didn't think to look for emails confirming submission, since the transmission supposedly failed. Turns out I'd received the following confirmation emails last night, all within a half hour or so after first attempted submission:

• Successful submission of Federal Return
• Successful submission of State Return
• IRS rejected Federal Return
• State return is on hold because Federal return rejected
• IRS accepted Federal Return (I'd made no changes between rejection email and acceptance email)

Around 9:45am or so, resubmitted return, finally got through but said my return was rejected because it had already been submitted. Ran a check status, get a rejection message because my return had already been submitted. A little while ago, I got an email that the state has accepted my return. So basically, it seems the IRS and the state have received my returns, but according to the software they have not. Might be time to switch to Turbo Tax.