MariaDB 10.4 Ubuntu 18.04 issue

I installed with success MariaDB 10.4 in our ubuntu 18.04.

Root user created with success and another local user for controlling only one database.

Although I notice that with command in ssh:

service mysql status

Mar 21 17:49:11 fresco systemd[1]: Started MariaDB 10.4.24 database server.
Mar 21 17:49:11 fresco /etc/mysql/debian-start[10798]: Upgrading MySQL tables if necessary.
Mar 21 17:49:11 fresco mysqld[10757]: 2022-03-21 17:49:11 9 [Warning] Access denied for user 'root'@'localhost' (using password: NO)
Mar 21 17:49:11 fresco /etc/mysql/debian-start[10801]: Looking for 'mysql' as: /usr/bin/mysql
Mar 21 17:49:11 fresco /etc/mysql/debian-start[10801]: Reading datadir from the MariaDB server failed. Got the following error when executing the 'mysql' command line client
Mar 21 17:49:11 fresco /etc/mysql/debian-start[10801]: ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
Mar 21 17:49:11 fresco /etc/mysql/debian-start[10801]: FATAL ERROR: Upgrade failed
Mar 21 17:49:11 fresco /etc/mysql/debian-start[10807]: Checking for insecure root accounts.
Mar 21 17:49:11 fresco mysqld[10757]: 2022-03-21 17:49:11 10 [Warning] Access denied for user 'root'@'localhost' (using password: NO)
Mar 21 17:49:11 fresco mysqld[10757]: 2022-03-21 17:49:11 0 [Note] InnoDB: Buffer pool(s) load completed at 220321 17:49:11

Fresco is a local user also.

Why I get these errors in mysql for root?

It is not making sense as when I login in mysql with root everything seems fine, all permissions are granted.

Any help please because I am confused?