Well I am trying to upload a application on iTunes but I get this error message ""Your account already has a valid iOS Distribution certificate"". As I understand I need to remove the certificate from the App. How can I do that ? if I am wrong, any idea how can i upload my app on iTunes?
I think I understand you're problem. You must be validating instead of submitting. In order to upload your app to iTunes Connect, in organizer, you must "Submit" your archive. This will upload it into iTunes connect.