Just updated to Xcode 7.1 and getting this error. Was able to upload fine using 7.0.1
Had the same issue and tried everything including Application Loader but still would not load into iTunes Connect. I'm running XCode 7.1.1 and OS X El Capitan.
I also have Avira (free version) installed and once I disable it, everything went through. Hope this helps someone.
Stackoverflow has been my savior and goto source for Obj C and now Swift!!