Error connecting to the database: No such file or directory

Fatal error: Uncaught Error: Interface 'CodeIgniter\Exceptions\ExceptionInterface' not found in /home/sakuramontessori.jp/public_html/libraries/CI/Database/Exceptions/DatabaseException.php:43 Stack trace: #0 /home/sakuramontessori.jp/public_html/libraries/autoload.php(35): require_once() #1 [internal function]: {closure}() #2 /home/sakuramontessori.jp/public_html/libraries/CI/Database/BaseConnection.php(425): spl_autoload_call() #3 /home/sakuramontessori.jp/public_html/libraries/CI/Database/BaseConnection.php(646): CodeIgniter\Database\BaseConnection->initialize() #4 /home/sakuramontessori.jp/public_html/libraries/CI/Database/BaseConnection.php(1883): CodeIgniter\Database\BaseConnection->query() #5 /home/sakuramontessori.jp/public_html/libraries/fstext.php(35): CodeIgniter\Database\BaseConnection->getObjectList() #6 /home/sakuramontessori.jp/public_html/index.php(106): FSText::load_languages() #7 {main} thrown in /home/sakuramontessori.jp/public_html/libraries/CI/Database/Exceptions/DatabaseException.php on line 43