Why does create sandbox for RTC 4.0.1 keep failing
One answer
I just tried this (creating just an RTC project area) and it also failed as it did for you. Looking at the activity feed, the other project areas that have been created are not RTC.
I've notified those responsible and they are getting it fixed. Should be working again very soon.
Thank you very much for reporting this (and your patience). Sorry for the inconvenience.