Ok so here are detailed steps on how to distribute:
You want to request a development and distribution certificate in Keychain Access and upload it to developer.apple.com (you are part of the developer member program right?)
Create an app ID (in provisioning profiles)
Create a distribution certificate - make sure this and step 2 follow your bundle ID
Download the profile and drag to Xcode
Go to your Xcode project, in the target or project build settings set your code signing option to the Distribution certificate (which must match your Bundle ID and of course your distribution and development certificate) - there might be a recommended or automatic profile, just choose the one that matches your identity and app provisioning profile and Bundle ID
Now go to edit scheme -> then change from debug to release
Then go to project than target than build settings and type in 'Code Signing', change the options to your distribution profile
Set to build for an iOS device (or none at all)
Go to product -> Build For -> Build For Archive
Scroll down on the side (your classes tab etc.) to the product which should be named (AppName.app) and show it in finder.
Create an application on iTunes Connect
Compress the .app and load it to Application Loader
Send it off!
Tips:
- Make sure you are using the correct Bundle ID
- Try cleaning
- Make sure you're certificate is not expired
Here is an expanded list of reasons why this may occur: