Use the following articles, if you encounter problems with your Sitefinity CMS website authentication functionality. These are some of the most common authentication issues you may have. If you do not find the solution to your problem, contact the support team.
Progress Knowledge Base articles:
How to troubleshoot authentication issues
This article describes the steps you need to make to investigate an authentication issue with your Sitefinity CMS website.
Windows Authentication: This configuration section cannot be used at this path for Sitefinity
This article describes the steps you need to make to address the error message This configuration section cannot be used at this path when running the WindowsAuthWebHost project required for Windows Authentication in Sitefinity 10.0 and above.
Disable Nonce validation for Non-default OpenIDProvider with Code
This article describes the steps you need to make to disable nonce validation for development under HTTP.
IMPORTANT: Disable nonce validation only for development and testing purposes and remove the code sample before deploying your website to production environment.
Browse the Sitefinity CMS Knowledge Base articles to find out more authentication-related troubleshooting information.
You can find further information on addressing authentication-related issues by visiting this hyperlink, which filters down the Sitefinity CMS Knowledge Base to display the most relevant resources on the topic.