Question Mysql with Docker - how to get permission?

[Sofie76]

Hello,

Ubuntu 20.04.4 LTS
Plesk Obsidian Version 18.0.41

1,

I installed Docker with mysql5.7 on Port 3308
I gave a password for MYSQL_ROOT_PASSWORD

2,

I added Database-Server

3,

I added a Database, select the Database-Server on Port 3308 (mysql5.7)
Create a new Database user with password.

4,

I imported a sql file into the new Database.

So far, everything works.

Now I have to connect to the database. My Config:

$dbhost = 'localhost';
$dbport = '3308';
$dbname = 'admin_test';
$dbuser = 'root';
$dbpasswd = 'mypassword';

Result:

Access denied for user 'root'@'localhost' [1698]

Then I tried the user I have added during the database creation .

Result:

Access denied for user 'mydatabaseuser'@'localhost' (using password: YES) [1045]

How is it possible to connect?

Thank you