How to setup phpMyAdmin to use cookie authentication
This guide will describe how to setup phpMyAdmin to use a cookie/session based login system.
The advantage of the cookie based logins is that you can get an exact mysql error as to why you can't login (if you can't login).
$cfg['blowfish_secret'] = '';
$cfg['blowfish_secret'] = 'anyrandomtextyouwant';
$cfg['Servers'][$i]['auth_type'] = 'http'; // Authentication method (config, http or cookie based)?
$cfg['Servers'][$i]['auth_type'] = 'cookie'; // Authentication method (config, http or cookie based)?
Close all browsers and try to connect again.
You may want to instead simply enable the one-click single-signon for phpMyAdmin which enables cookies by default:
One-Click login to RoundCube and phpMyAdmin