Why is my URL shortener suddenly rejecting all links?

Since this was a learning project, make sure to recheck your setup. Check if your deployment environment is still intact. Sometimes server settings can change unexpectedly.

Have you tried debugging yet? It’s really essential to learn how to debug your code. Look into your logs, use a debugger, and handle any errors appropriately. These fundamentals will help you track down the problem.

From what you've described, it sounds like the issue could be related to either the client side or the server side. Since it was working fine before, start by checking for any recent changes or issues with your server configuration.

Also, if you're not using any libraries or frameworks to handle the URLs, consider looking into basic error handling routines. It might just be a small oversight that’s causing the rejections.