Cannot install postfixadmin on AWS EC2 instance about postfixadmin HOT 3 CLOSED

// Database connection details.
$CONF['database_type'] = 'mysqli';
$CONF['database_host'] = 'localhost';
$CONF['database_user'] = 'postfix';
$CONF['database_password'] = 'postfixadmin';
$CONF['database_name'] = 'postfix';

from postfixadmin.

MySQL Connection Tester

Connection test result: PASSED

Host name: localhost
Database name: postfix
Username: postfix
Password: postfixadmin

Test Connection

from postfixadmin.

DEBUG INFORMATION:
MySQL 3.x / 4.0 functions not available! (php5-mysql installed?)
database_type = 'mysql' in config.inc.php, are you using a different database?

This is a very strong indication that you have $CONF['database_type'] = 'mysql'; somewhere, and that it overrides the mysqli in the config you pasted above. (If in doubt, grep your config files for "database_type".)

from postfixadmin.