Cannot login to phpMyAdmin, no errors shown

This is a possible issue when the path to save php_session is not correctly set :

The directory for storing session does not exists or php do not have sufficient rights to write to it.

To define the php_session directory simply add the following line to the php.ini :

session.save_path="/tmp/php_session/"

And give write rights to the http server.

usually, the http server run as user daemon in group daemon. If it is the case, the following commands will make it :

chown -R :daemon /tmp/php_session

chmod -R g+wr /tmp/php_session

service httpd restart

Login fails if session folder in not writeable. To check that, create a PHP file in your web directory with:

<?php
$sessionPath = 'undefined';

if (!($sessionPath = ini_get('session.save_path'))) {
    $sessionPath = isset($_ENV['TMP']) ? $_ENV['TMP'] : sys_get_temp_dir();
}

if (!is_writeable($sessionPath)) {
    echo 'Session directory "'. $sessionPath . '"" is not writeable';
} else {
    echo 'Session directory: "' . $sessionPath . '" is writeable';
}

If session folder is not writeable do either

sudo setfacl -R -m u:www-data:rwx <session directory> or chmod 777 sudo setfacl -R -m u:www-data:rwx <session directory> -

I am late to the game, but on Amazon linux AMI I could not log in to phpmyadmin ... it just kept refreshing the login screen with no errors.

I have fixed with below command

sudo chmod -R 755 /var/lib/php/session