# Critical Error: SiteUrls.Config Specific Error Message: [SiteUrlData] Please contact your site administrator. An explanation for why this error could occur is below.
Community Server expects to find a valid XML file containing all of the links for a community. By default, this file is located at the root of the with the name SiteUrls.config. A common error is that SiteUrls.config included unescaped XML characters, such as "&" when defining a querystring. For more information you can also visit http://communityserver.org.