Why does my sitemap have gray links?

The gray links in your XML sitemap identify the URLs that your browser has recently visited. As this is browser-specific, you may or may not see different gray URLs depending on the browser and computer you are using to view your sitemap.

So, there’s no reason for concern; you don’t have to do anything.

Please note that Google does not see the browser formatting as they retrieve the xml source code. If you’re getting a different error, check out this article on common XML sitemap errors to see more errors, their causes, and their solutions.