Resolving the "No CORS Policy Found" Error in Sitecore 10.3 Identity Server

Encountering the Sitecore Identity Server error, specifically the "No CORS policy found for the specified request" issue, can be a frustrating experience for developers and administrators. In this blog post, we'll delve into the details of this error and provide a practical solution to address it.

Error Details:

The error message points to a problem with the CORS (Cross-Origin Resource Sharing) policy, specifically when the request origin is set to "null," indicating that it doesn't have permission to access the resource. The log entries show the execution of the relevant endpoint in the Identity Server, followed by an unhandled exception related to a SQL Server connection issue.

Error Log:

(Sitecore Identity/AA0001) Request origin "null" does not have permission to access the resource.

(Sitecore Identity/AA0001) No CORS policy found for the specified request.

(Sitecore Identity/AA0001) Executing endpoint '"Sitecore.Plugin.IdentityServer.Controllers.AccountController.Login (Sitecore.Plugin.IdentityServer)"'

[INF] (Sitecore Identity/AA0001) Route matched with "{action = \"Login\", controller = \"Account\"}". Executing controller action...

[INF] (Sitecore Identity/AA0001) Executed action "Sitecore.Plugin.IdentityServer.Controllers.AccountController.Login (Sitecore.Plugin.IdentityServer)" in 16964.3894ms

[ERR] (Sitecore Identity/AA0001) An unhandled exception has occurred while executing the request.

System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server...

 ---> System.ComponentModel.Win32Exception (2): The system cannot find the file specified.

Solution:

To address this issue, follow these steps:

Investigate the CORS Policy:

Check your Sitecore configuration and ensure that the CORS policy is correctly configured to allow the specified request origin. Review Sitecore documentation and relevant articles to verify the proper CORS setup.

Review External Resources:

The provided Sitecore Stack Exchange link (https://sitecore.stackexchange.com/questions/19242/what-does-this-error-message-in-the-identity-server-logs-mean) can offer valuable insights into similar issues. Explore discussions and solutions from the community.

Check SQL Server Services:

In the presented solution, the root cause was identified as SQL Server services not running. Validate the status of your SQL Server services and restart them if necessary. Ensure that SQL Server is configured to allow remote connections and that the instance name is correct.

Conclusion:

Resolving the "No CORS policy found for the specified request" issue in Sitecore Identity Server involves a comprehensive approach. By investigating the CORS policy, reviewing external resources, and addressing potential SQL Server service issues, you can successfully mitigate this error. Remember to adapt these steps based on your specific environment and configurations.