Warning: mysqli_connect(): php_network_getaddresses: getaddrinfo for portal_db failed: Name or service not known in /var/www/html/functions/get_db_prefix.php on line 5

Fatal error: Uncaught mysqli_sql_exception: php_network_getaddresses: getaddrinfo for portal_db failed: Name or service not known in /var/www/html/functions/get_db_prefix.php:5 Stack trace: #0 /var/www/html/functions/get_db_prefix.php(5): mysqli_connect('portal_db', 'portal', Object(SensitiveParameterValue), 'portal_db', '3306') #1 /var/www/html/functions/connect_db.php(3): include('/var/www/html/f...') #2 /var/www/html/index.php(45): include('/var/www/html/f...') #3 {main} thrown in /var/www/html/functions/get_db_prefix.php on line 5