Recently, we encountered this error on one of our servers, and here’s how we resolved it. Additional Errors Displayed on Screen Job for mariadb.service failed because the control process exited with error code. See "systemctl status mariadb.service" and "journalctl -xe"

If you're encountering the "ERROR 1273 (HY000): Unknown collation: 'utf8mb4_unicode_520_ci'" issue, it's likely because your MySQL or MariaDB server does not support the utf8mb4_unicode_520_ci collation. This collation was introduced in MySQL 5.7.6 and may not be available on older versions