Merge pull request #6838 from DeadMonkeyX/feat/Heartcore-external-login-providers

feat: Update documentation on external login providers and bearer tokens

Author: sofietoft

umbraco-heartcore/api-documentation/README.md

@@ -107,7 +107,11 @@ Api-Key: {api-key}
 
 ### Bearer token
 
-The endpoints implements OAuth 2.0.
+{% hint style="info" %}
+This feature is currently not available when using [External Login Providers.](../../umbraco-cloud/set-up/external-login-providers.md)
+{% endhint %}
+
+The endpoints implement OAuth 2.0.
 
 A bearer token can be created by posting to `https://api.umbraco.io/oauth/token` and supplying a username and password for a backoffice user.
 This corresponds to a user logging into the backoffice and is thus only meant to be used for the Content Management API.