title: Cocoapods: Unable to find a specification for `Firebase/Core`
body: <p>I have this in podfile:</p>
  
  <pre><code>pod 'Firebase/Core'
  pod 'Firebase/Messaging'
  </code></pre>
  
  <p>but getting this error:</p>
  
  <blockquote>
    <p>[!] Unable to find a specification for <code>Firebase/Core</code></p>
  </blockquote>
  
  <p>i tried with <code>pod 'Firebase'</code> still can't find it.</p>
  
  <p>Podfile:</p>
  
  <pre><code># Uncomment this line to define a global platform for your project
  # platform :ios, '8.0'
  # Uncomment this line if you're using Swift
  use_frameworks!
  
  target 'caffetouch manager' do
      pod 'Firebase/Core'
      pod 'Firebase/Messaging'
      pod 'Alamofire', '~&gt; 4.0.0'
      pod 'AlamofireNetworkActivityIndicator', '~&gt; 2.0.1'
      pod 'IQKeyboardManagerSwift', '~&gt; 4.0.6'
      pod 'MZFormSheetPresentationController', '~&gt; 2.4.2'
      pod 'Kingfisher', '~&gt; 3.1.3'
      pod "GMStepper"
      pod 'DKImagePickerController', '~&gt; 3.4.0'
      pod 'Siren', '~&gt; 1.0.2'
      pod 'Eureka', '~&gt; 2.0.0-beta.1'
      pod 'SwiftyJSON'
      pod 'ObjectMapper', '~&gt; 2.1'
      pod 'NVActivityIndicatorView'
      pod 'SwiftDate', '~&gt; 4.0.5'
      pod 'SimpleAlert' '~&gt; 2.0.1'
  
      pod 'BTNavigationDropdownMenu', :git =&gt; 'https://github.com/PhamBaTho/BTNavigationDropdownMenu.git', :branch =&gt; 'swift-3.0'
      pod 'ENSwiftSideMenu', :git =&gt; 'https://github.com/evnaz/ENSwiftSideMenu.git', :branch =&gt; 'master'
      pod 'SkyFloatingLabelTextField', git: "https://github.com/MLSDev/SkyFloatingLabelTextField.git", branch: "swift3"
  end
  
  
  post_install do |installer|
    installer.pods_project.targets.each do |target|
      target.build_configurations.each do |config|
        config.build_settings['SWIFT_VERSION'] = '3.0'
      end
    end
  end
  </code></pre>