On a development server, at least once this situation occurs when the MySQL won’t set up with a root password.
You will get an error as “Login without a password is forbidden by configuration (see AllowNoPassword)” as shown below:
You can easily enable the ability to manage MySQL via phpMyAdmin (when the root login has no password). It is as easy as changing two lines in the configuration file.
Let’s set the AllowNoPassword variable, included in phpMyAdmin’s configuration file, to TRUE. On an Ubuntu 18.04 LTS server, modify the below file: