CocoaPods pod spec lint Fails on Embed Pods Frameworks

I'm getting the following error when trying to run pod spec lint --verbose:

    ** BUILD FAILED **


    The following build commands failed:
        PhaseScriptExecution [CP]\ Embed\ Pods\ Frameworks /Users/myuser/Library/Developer/Xcode/DerivedData/App-loplmnuztwibrzfqgadqoxucytrz/Build/Intermediates.noindex/App.build/Release/App.build/Script-09EB8340PON5K18DNW0C63DQ.sh
    (1 failure)
   Testing with `xcodebuild`. 
 -> MySwiftPackage (0.1.0)
    - WARN  | summary: The summary is not meaningful.
    - WARN  | description: The description is shorter than the summary.
    - WARN  | url: The URL (https://github.com/fishcharlie/MySwiftPackage) is not reachable.
    - NOTE  | xcodebuild:  note: Using new build system
    - NOTE  | xcodebuild:  note: Planning build
    - NOTE  | xcodebuild:  note: Constructing build description
    - NOTE  | [iOS] xcodebuild:  warning: Skipping code signing because the target does not have an Info.plist file. (in target 'App')
    - WARN  | xcodebuild:  MySwiftPackage/MySwiftPackage/ViewControllers/Shared/MyFirstViewController.swift:102:37: warning: conditional cast from 'UIViewController' to 'MyViewController' (aka 'UIViewController') always succeeds
    - WARN  | xcodebuild:  MySwiftPackage/MySwiftPackage/ViewControllers/Shared/MySecondViewController.swift:145:37: warning: conditional cast from 'UIViewController' to 'MyViewController' (aka 'UIViewController') always succeeds
    - ERROR | [OSX] xcodebuild: Returned an unsuccessful exit code.

Analyzed 1 podspec.

[!] The spec did not pass validation, due to 1 error and 5 warnings.

I know I have a few warnings that I can clean up. But there is only one error that I'm getting, which is - ERROR | [OSX] xcodebuild: Returned an unsuccessful exit code.. And above that it says that Embed Pods Frameworks was the cause of failure.

Not quire sure how to debug this since I can build and run the example projects in Xcode just fine.

Below I have attached my Podspec as well.

Pod::Spec.new do |s|
  s.name             = 'MySwiftPackage'
  s.version          = '0.1.0'
  s.summary          = 'A short description of MySwiftPackage.'

  s.description      = <<-DESC
TODO: Add long description of the pod here.
                       DESC

  s.homepage         = 'https://github.com/fishcharlie/MySwiftPackage'
  s.license          = { :type => 'MIT', :file => 'LICENSE' }
  s.author           = { 'fishcharlie' => 'fishcharlie.code@gmail.com' }
  s.source           = { :git => 'https://github.com/fishcharlie/MySwiftPackage.git', :tag => s.version.to_s }
  s.social_media_url = 'https://twitter.com/char_fish'

  s.ios.deployment_target = '9.0'
  s.osx.deployment_target = '10.11'
  s.swift_version = '4.2'

  s.source_files = 'MySwiftPackage/Classes/**/*', 'MySwiftPackage/ViewControllers/Shared/**/*'
  s.ios.source_files = 'MySwiftPackage/ViewControllers/iOS/**/*'
  s.osx.source_files = 'MySwiftPackage/ViewControllers/macOS/**/*'
  s.resources = 'MySwiftPackage/Assets/**/*.{ttf,xcassets}'

  s.dependency 'Alamofire', '4.7.3'
  s.dependency 'Bond', '6.10.2'
  s.ios.dependency '1PasswordExtension', '1.8.5'
end

Any ideas on how to fix/debug this?

from CocoaPods pod spec lint Fails on Embed Pods Frameworks