You will get the below error when logging in to phpMyAdmin without a password, even if your actual MySQL account itself is passwordless. It is because phpMyAdmin is normally configured to disable passwordless login due to security reasons.

Login without a password is forbidden by configuration (see AllowNoPassword)

To enable log in to MySQL / MariaDB with no password in phpMyAdmin, you'll need to configure AllowNoPassword option in phpMyAdmin's configuration.

Steps to allow no-password login to MySQL / MariaDB in phpMyAdmin:

  1. Make sure your MySQL or MariaDB user is passwordless and accessible by phpMyAdmin's system user.

    User root by default requires system's administrator privilege to log in.
    Related: How to connect to root MySQL account without sudo

  2. Open phpMyAdmin configuration file using your preferred text editor. 

    $ sudo vi /etc/phpmyadmin/config.inc.php

    Related: phpMyAdmin configuration file

  3. Search for Servers → AllowNoPassword options and set the value to TRUE. 

    $cfg['Servers'][$i]['AllowNoPassword'] = TRUE;

    Remove // at the start of the line if exist to uncomment the option.

    Depending on distributions, there could be multiple occurrences of that particular line. Ubuntu for example has the following 2 lines; 

    if (!empty($dbname)) {     // other configuration options     $cfg['Servers'][$i]['AllowNoPassword'] = TRUE;     // it should be placed before the following line     $i++; }   // other configuration options $cfg['Servers'][$i]['AllowNoPassword'] = TRUE;

  4. Save and exit the text editor.
  5. Log in again via phpMyAdmin without password.