When you try to add or edit an RSS feed and the system says it's invalid, it could be caused by one of the following reasons:
- The feed URL was mistyped or not fully selected when copied.
- The RSS feed could be taking more than 5 seconds to respond. We don't interact with feeds that take more than 5 seconds to respnd when accessed.
- A firewall on the server that hosts the RSS feed, or something on the network in front of the RSS feed, is blocking our servers from accessing the RSS feed.