Merge pull request #748 from kinde-oss/feat/add-4321-error-code

feat: add new error code description and troubleshooting for 4321

Author: tamalchowdhury

src/content/docs/get-started/guides/error-codes.mdx

@@ -250,6 +250,20 @@ Description
 Troubleshooting
 - Check the secret being used with your social provider and ensure that it hasn't expired
 
+## Error code 4321
+
+Description
+- This error typically occurs when a user attempts to access an authentication flow from a mid-step URL instead of starting from the beginning.
+- Reasons this error may occur:
+  - A bookmarked or previously used URL is reused
+  - A step-specific URL is shared directly
+  - The user navigates back or forward in the browser and skips required steps in the flow
+
+Troubleshooting
+- Ask the user to restart the login flow from the main entry point, such as your app’s login page
+- Clear browser cookies and cache before retrying
+- Avoid using any bookmarked or shared login URLs
+
 ## Error code 4617
 
 Description