I just had this issue 3 times this morning. I signed up for the 9:30 am flex, then the system messed up. So I quickly signed up for 9:50 am and the system messed up again. Then was on the phone with proctoru for over an hour and they couldn't figure out what was going on. So I called LSAC and they were like sorry bruh just submit a complaint and try to reschedule. Did that and rescheduled and the same issue. I even reinstalled the ProctorU extension and restarted the whole comp. Guess November it is.