I WAS ABLE TO EFILE AFTER REATTACHING FORM 8453-FE! In my case, even though nothing changed in my return, I decided to go through the entire process of printing, signing, scanning and then reattaching just to make sure and IT WORKED!!!
THANK YOU to the INTUIT CUSTOMERS who solved it.
NOTE TO INTUIT: Even though the tech team did not figure out the problem and it was customers who eventually figured this out, thank you to @KristinaK who collected logs and brought them to the tech team for help. The only advice on that would have been to post updates so people know Intuit is looking into it.
ADVICE TO INTUIT: You really need to point your AI to this community forum and have it report to you on threads where customers are struggling and asking for your help. It could even report HIGH PRIORITY BUGS (which this is) so the tech team could be notified immediately. The feedback loop is broken here and AI could help on that.
