One of the most common reasons your Xtream UI installation fails during database setup is either a conflict with an existing MySQL root password or a misconfigured timezone setting. Make sure MySQL is running and that your MySQL root user is accessible with the password set by the Xtream UI script. You can reset it using mysqladmin -u root password 'yourpassword'. Also, confirm that your server time is correctly synced via timedatectl. In some cases, re-running the installer with sudo can bypass permission errors. Always check install.log for clues.