From TMM Wiki
You should validate a feed you intend on distributing. If a feed does not validate, some of your intended readers may not be able to read the feed. The following five steps explain how to validate a RSSDish feed.
- Log into RSSDish
- Click the RSS Viewer
- Select the RSSDish feed, or type the external URL, of the feed you wish to validate.
- Use the links next to the blue check mark to validate the selected feed. (Note: RSSDish uses a third party site, feedvalidator.org, for validation)
- View the results of the validation and fix any errors.