Short Answer 
To resolve the ‘sssd couldn’t load the configuration database’ error, check the SSSD configuration file for syntax issues, verify that the file permissions are set to 600 and owned by root, and then clear the cache using `sudo sss_cache -E` followed by restarting SSSD with `sudo systemctl restart sssd`. If problems continue, consider recreating the configuration file.
1. Check the SSSD Configuration File
Begin by verifying the SSSD configuration file located at /etc/sssd/sssd.conf. Look for any syntax errors or misconfigurations that may be causing the issue. Ensure the format is correct and all required fields are filled out accurately. Issues in the configuration file can lead to the inability to load the database.
2. Verify File Permissions
Next, check the permissions of the configuration file to ensure they are set correctly. The permissions should be set to 600, meaning only the owner can read and write the file. Additionally, confirm that the file is owned by the appropriate user, typically root. Incorrect permissions can prevent SSSD from accessing the file properly.
3. Clear the Cache and Restart SSSD
If the configuration file is correct and permissions are set properly, clear the SSSD cache using the command sudo sss_cache -E. This will remove any stale cached data that might be causing issues. After clearing the cache, restart the SSSD service with sudo systemctl restart sssd to apply the changes. If problems persist, consider recreating the configuration file or restoring it from a backup.