xcancel is just one Nitter instance (just like lemmy.ml is one Lemmy instance). I recommend sharing the load around to other working instances, or better yet, as Avatar of Vengeance mentioned, use the LibRedirect browser extension which automates this for a huge range of other websites.

https://libredirect.github.io/

The future is now

Please make an effort to avoid X.

If you’re looking for someone’s or an organization’s feed, look for alternatives such as:

• Look for that person’s Mastodon account,
• Look for a blog or website. It may have a RSS feed, if not try https://fetchrss.com/generator/generate
• Look for a bluesky account, and get its RSS feed with a tool like https://fetchrss.com/generator/generate