When trying to upload an App to iTunes connect in Xcode 8.3.3, I get the error:
iTunes Connect access for \"Team-Name\" is required. Add an account in
Had the same stupid problem.
Ultimately exported the .ipa to disk (via Xcode itself) and used altool
command line tool to upload the ipa. It worked!!
altool --upload-app -f YourIpa.ipa -u
Apple should really spend some $$$ on improving Xcode and the overall Developer experience. Its painful.
I again went back to Xcode to try and upload but met with the same error, so command line was indeed helpful.