This article explains the cause of the following error when trying to build the React Native Sample App (00-Login folder), which prevents the app from being completed and started up.

• Error:
  [!] CocoaPods could not find compatible versions for pod “Auth0”:
  In snapshot (Podfile.lock):
  Auth0 (= 2.4.0)
• In Podfile:
  A0Auth0 (from ../node_modules/react-native-auth0) was resolved to 3.0.0, which depends on
  Auth0 (= 2.5.0)

The error happens after following these steps: 

1. yarn install 
2. cd ios
3. pod install and then an error is thrown

• React Native v4.5.0 
• react-native-sample app (00-Login folder) (Fixed in this commit)

Using out-of-date source repos/pods

• react-native-sample app (00-Login folder) was referencing older versions of those dependencies
• React Native v4.5.0 A0Auth0.podspec file updated the Auth0, JWTDecode, and SimpleKeychain dependencies
• React Native v4.5.0 Podfile.lock file was updated to use the A0Auth0 4.4.0, Auth0 2.10, JWTDecode 3.2.0, and SimpleKeychain 1.2.0 pods

Use the latest auth0-react-native sample app to resolve the dependency issue. It was recently fixed through this commit.

Another option is to update the pod dependencies to the latest versions. 

While in the iOS folder,  update the out-of-date source repos with the following commands:

pod repo update 

pod update Auth0

or with

pod install --repo-update