I got the same error message last week so I tried again today with a clean set of input and got the same error message. I switched to Forms view and found one for "Schedule C (unnamed)" which is for a Business Owner. I have never owned or run any business so I have no idea why that form was in my return other than it may have carried over from a previous year's data. I may have tried to claim some of my home as office space once in the past. (The Standard Deduction was better for me so no need to keep un-needed forms TT.)
The form was not easy to delete, but I finally managed to delete it. (The menu option to delete did not work, only the Delete button in the form view.) After that, I was able to e-file with no issues.
Another reason may just be "luck" as it is January 29, 2024 and perhaps the e-file servers just got updated to start accepting Federal returns!
