I had the same problem, I think there is a problem with their new interface. When you select the binary you uploaded, there is a small red delete button that shows, but when you select it, it does nothing. I tried to save after the selection also, didn’t seem to make a difference.
After many frustrating clicks, I decided to change the version number of the app and the uploader allowed it to go through.
The new format looks like it will allow you to select a binary from the list, but the uploader doesn’t work with it. Apple needs fixing.
Nail