What kind of "additional information" could they need?

Hello,

I have an upcoming trip (less than two weeks now) and applied for a passport with expedited service. Tuesday was the "less than two weeks" day for me so I called the number that morning, they said they would notify the agency of impending travel. That afternoon my status changed from "In Progress" to "Additional Information Needed".

Looking over my application there is a chance that my mother's name on my application is her married name and not her maiden name as is on my birth certificate. Would that be the cause?

Also, despite my email being on the application and having signed up for email alerts, I not received an email (I've whitelisted state.gov just in case). Is this normal?

If so, what "additional information" could I provide to fix a (basic, stupid) mistake? My mom has been dead since 2005 and I don't have access to any official records for her to establish identity. In a panic, I made an appointment at the same agency handling my doing my application. Will it be a problem if I go to the appointment and effectively re-apply?

What else could it be in terms of "additional information"?

Sorry, my anxiety is through the roof over this, and I am looking for some advice on the next steps/what to expect.