Why does Spotify for Creators say my RSS feed is invalid when it opens in a browser?

Because loading in a browser only proves the URL is reachable; Spotify still has to parse it as a valid podcast feed. Double-check that you pasted the actual RSS URL, not your show's public page, then run that feed through a validator. A malformed tag or missing required show info can trigger a validation error even when the XML opens normally. If the validator points to something you can't edit, your podcast host is the right place to get it fixed. If you changed the feed's owner email, give Spotify a little time to pick up the update before trying again.