I am uploading iPhone application using latest xCode 8. I have good internet connection and all the relevant settings set up at iTunes connect. My distribution profiles are also set up correctly.
I am facing below error:-
iTunes software service authentication error domain error 434
So this has what worked for me:
Preface: 4 days of debugging, recreated certificates numerous times, nothing worked, every time i try to validate/upload via Xcode it says same error "iTunes software service authentication error domain error 434"
Solution without XCode:
Solution with XCode: