fastlane: undefined method `map' for nil:NilClass

Issue Description

Complete output when running fastlane, including the stack trace and command used

+------------------------------------------------------------------------------+
| (0) deploy-to-itunesconnect-deliver@2.6.1                                    |
+------------------------------------------------------------------------------+
| id: deploy-to-itunesconnect-deliver                                          |
| version: 2.6.1                                                               |
| collection: https://github.com/bitrise-io/bitrise-steplib.git                |
| time: 2016-08-19T10:29:51-07:00                                              |
+------------------------------------------------------------------------------+
|

Config:
 * ipa_path: /Users/vagrant/deploy/AppName.ipa
 * pkg_path: 
 * itunescon_user: someemail
 * password: ***
 * app_id: APPID
 * submit_for_beta: no
 * skip_metadata: yes
 * skip_screenshots: yes
 * team_id: 
 * team_name: 
 * update_deliver: yes

# Setup

 (i) deliver already installed
 (i) updating  deliver...

 (i) Which ruby: /usr/local/bin/ruby
 (i) Ruby version: ruby 2.2.4p230 (2015-12-16 revision 53155) [x86_64-darwin15]

 -> using brew (/usr/local/bin/ruby) ruby
$ gem install deliver --no-document
Successfully installed spaceship-0.31.3
Successfully installed fastlane_core-0.50.2
Successfully installed deliver-1.13.2
3 gems installed

 (i) Setup took 3 seconds to complete


# Deploy


**Note:** if your password
contains special characters
and you experience problems, please
consider changing your password
to something with only
alphanumeric characters.


**Be advised** that this
step uses a well maintained, open source tool which
uses *undocumented and unsupported APIs* (because the current
iTunes Connect platform does not have a documented and supported API)
to perform the deployment.
This means that when the API changes
**this step might fail until the tool is updated**.

[10:30:02]: Login to iTunes Connect (emailaddress)
[10:30:04]: Login successful

+--------------------+----------------------------------+
|                deliver 1.13.2 Summary                 |
+--------------------+----------------------------------+
| ipa                | /Users/vagrant/deploy/appname.ipa |
| skip_screenshots   | true                             |
| skip_metadata      | true                             |
| force              | true                             |
| app_identifier     | com.AppName.app.AppName            |
| screenshots_path   | ./screenshots                    |
| metadata_path      | ./metadata                       |
| app_version        | 1.0.0                            |
| username           | email                 |
| skip_binary_upload | false                            |
| submit_for_review  | false                            |
| automatic_release  | false                            |
+--------------------+----------------------------------+

[10:30:05]: Making sure the latest version on iTunes Connect matches '1.0.0' from the ipa file...
[10:30:06]: '1.0.0' is the latest version on iTunes Connect

Looking for related GitHub issues on fastlane/fastlane...

[10:30:07]: Error finding relevant GitHub issues: undefined method `map' for nil:NilClass

[!] The request could not be completed because:
    Screenshots and app previews for the largest display sizes of your app’s primary localization must be uploaded directly. Screenshots and app previews for the largest display sizes of your app’s primary localization must be uploaded directly. Screenshots and app previews for the largest display sizes of your app’s primary localization must be uploaded directly. Screenshots and app previews for the largest display sizes of your app’s primary localization must be uploaded directly. Screenshots and app previews for the largest display sizes of your app’s primary localization must be uploaded directly. Screenshots and app previews for the largest display sizes of your app’s primary localization must be uploaded directly. There is an error for 1 of your localizations.
 [!] Error description: Deploy failed!
     (i) Exit code was: 1
 (i) Calling cleanup function before exit
-> finalcleanup

# Error


**Error Description**:


Deploy failed!


*See the logs for more information*


**If this is the very first build**
of the app you try to deploy to iTunes Connect then you might want to upload the first
build manually to make sure it fulfills the initial iTunes Connect submission
verification process.

Environment

Using Bitrise - Xcode 7.3.1, on OS X 10.11.4

I asked their support and they have said its an issue with fast lane. I submitted the app manually via Xcode on my local machine and it worked fine, so i know that there is nothing wrong with the app/code.