Getting error mysqli::real_connect(): (HY000/2002): No such file or directory when I try to access my project on live server

MySQL connection driver does not get any meaningful server at the location of localhost. So use,

'hostname' => '127.0.0.1' 

rather than

'hostname' => 'localhost'

Same problem occurd with me, with AWS RDS MySQL. Looked various sources, but as of this thread, almost all lack of answer. While this answer helped me, tweak in mind to update hostnames at server. Access your SSH and follow the steps:

cd /etc/
sudo nano hosts

Now, Appending here your hostnames: For example:

127.0.0.1 localhost
127.0.0.1 subdomain.domain.com [if cname redirected to endpoints]
127.0.0.1 xxxxxxxx.xxxx.xxxxx.rds.amazonaws.com [Endpoints]

and now, configuring config/database.php as follows:

$active_group = 'default';
$query_builder = TRUE;

$db['default'] = array(
    'dsn'   => '',
    'hostname' => '35.150.12.345',
    'username' => 'user-name-here',
    'password' => 'password-here',
    'database' => 'database-name-here',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => TRUE,
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

where 35.150.12.345 is your IPv4 Public IP, located at ec2-dashboard > Network Interfaces > Description : RDSNetworkInterface >> IPv4 Public IP('35.150.12.345') there.

Note: Please note that only IPV4 will work at 'hostname' option. hostname, cname, domains will output database connection error.

I've got this error

mysqli::real_connect(): (HY000/2002): No such file or directory

from PhpMyAdmin running on my Mac Mojave, with MySQL server also running on my Mac.

Fixed it by editing PhpMyAdmin/config.inc.php and changed the line:

$cfg['Servers'][$i]['host'] = 'localhost';

to

$cfg['Servers'][$i]['host'] = '127.0.0.1';