I've been having the same issues. I had been working on App A in beta-9 for a while and kept getting this error. So when Gm came out, I hoped that would resolve the issue. No dice. I even tried creating a clean dummy test app (App B) with fresh provisioning profiles to be certain it wasn't the app or the PPs. App B didn't work either. So I went to bed.
I got up the next morning and it passed validation, no error, hadn't touched a thing. So naturally, I opened up App B to see if that was now working but it was not. I think while I was tinkering with App B, I may have flipped on "Auto manage signing" because it's the only way you can select a team (dumb) which caused Xcode to generate another cert. D'oh! This may have been my fatal error... I loaded up the previously validated App A and boom, same error message again.
I spent some time today deleting all my certs and profiles, cleaned out keychain, etc. Started totally fresh, still not working. I gave it about 5 hours and tried again, still busted. I'm hoping it's a caching thing or a maybe just Apple's servers being borked due to load around the announcement and GM's going out. Will try again tomorrow and report back if I figure anything out.
Please let me know if you find the problem/solution. For the record, I have 2 teams tied to my ID, but I'm an Agent for one and full-power Admim for the other... so the idea that I wouldn't have iTunes Connect access is doubly laughable.