Recently, Vercel made Deployment Protection the default for all new projects in Vercel. This is great news! This means that all your deployments will automatically be able to be secured with authentication, passwords, or trusted IPs.
However, your Sitecore XM Cloud build might not be set up yet to work with Vercel’s Deployment Protection. You may encounter a 401 authentication error (unauthorized) when accessing static assets for things like CSS where your Next.js application is trying to use the VERCEL_URL to access these assets.
Read article to find out how to handle this in your build! ➡ https://jasonstcyr.com/2023/11/06/sitecore-xm-cloud-and-vercel-deployment-protection/