When setting up Matomo, if you’re facing an error « SQLSTATE[HY000][2054] The server requested authentication method unknown to the client », it is likely that you are using MySQL version 8.X. In MySQL 8.X, « caching_sha2_password » is the default authentication plugin (whereas in MySQL 5.7 and prior it used to be mysql_native_password »), which can cause some issues.

To solve this issue, do either one of the following:

1) Update your existing Matomo DB user and set the appropriate authentication type by executing the following SQL query:

UPDATE `mysql`.`user` 
SET `plugin` = 'mysql_native_password' 
and (`User` = 'YOUR MATOMO DB USER NAME');

or alternatively:

2) Create a new database and database user in MySQL by running the SQL queries from this FAQ, and then update your matomo/config/config.ini.php file to reference this new DB user.