The error message "login.OAuthLogin(missing saved state)" in Grafana typically indicates an issue with the OAuth authentication process. This error occurs when Grafana is expecting a saved state during the OAuth login flow but doesn't receive it.

To address this issue, you can try the following steps:

1. Clear Browser Cache and Cookies:

   • Clear your browser's cache and cookies to ensure that there are no stored or conflicting authentication states.

2. Check OAuth Configuration:

   • Verify that the OAuth configuration in Grafana is set up correctly. Make sure that the client ID, client secret, redirect URL, and other OAuth settings match the configuration provided by your OAuth provider.

3. Check Clock Synchronization:

   • Ensure that the system clocks on the server running Grafana and the OAuth provider are synchronized. OAuth tokens often have expiration times, and if the clocks are significantly out of sync, it can cause authentication issues.

4. Verify OAuth Provider Settings:

   • Double-check the settings on your OAuth provider (e.g., Google, GitHub, etc.). Ensure that the redirect URL configured there matches the URL configured in Grafana.

5. Test OAuth Flow with Provider:

   • If possible, test the OAuth flow directly with your OAuth provider using tools like Postman or a web browser. This can help verify that the provider is correctly generating and returning the OAuth tokens.

6. Check for Grafana Updates:

   • Ensure that your Grafana installation is up-to-date. If there are known issues related to OAuth, they may have been addressed in newer versions.

7. Review Grafana Logs:

   • Check the logs of your Grafana instance for any error messages or warnings related to the OAuth authentication process. This might provide more specific information about the issue.

8. Reconfigure OAuth in Grafana:

   • If all else fails, consider reconfiguring the OAuth settings in Grafana. Delete the existing OAuth configuration, and set it up again with the correct credentials and settings.

9. Contact Grafana Support or Community:

   • If the issue persists, consider reaching out to Grafana's support or community forums for specific guidance based on your setup.

Remember to always back up your Grafana configuration before making significant changes, and to test any changes in a controlled environment if possible.