Add social connection api key unauthorized error warning

README.md

@@ -3,6 +3,8 @@
 This extension provides a rule and interface for giving users the option of linking a new account
 with an existing registered with the same email address from a different provider.
 
+> **NOTE:** Please make sure you are using your own social connections (Google, Facebook, etc...) API keys. Using Auth0's keys will result on an 'Unauthorized' error on account linking skip.
+
 ## Example:
 - You signed up with FooApp with your email, `[email protected]`.
 - You come back some time later and forget whether you signed in with your email or Google account with the same email address.
@@ -13,6 +15,7 @@ with an existing registered with the same email address from a different provide
 
 ## Running in Development
 
+
 Update the configuration file under `./server/config.json`:
 
 ```json
@@ -35,7 +38,7 @@ yarn run serve:dev
 
 ## Running puppeteer tests
 
-In order to run the tests you'll have to [start the extension server locally](https://github.com/auth0-extensions/auth0-account-link-extension#running-in-development), fill the `config.test.json` file (normally with the same data as the `config.json` file) and run the Sample Test application located in `sample-app/` (same domain and client settings as the extension).
+In order to run the tests you'll have to [start the extension server locally](https://github.com/auth0-extensions/auth0-account-link-extension#running-in-development), fill the `config.test.json` file (normally with the same data as the `config.json` file) and run the Sample Test application located in `sample-app/` (create a dedicated client for this app).
 
 Then, you can run the tests running:
 ```bash