SequelizeConnectionError: Client does not support authentication protocol requested by server; consider upgrading MariaDB client
I found the answer:
login to mysql command line and write the following commands:
use mysql;
update user set authentication_string=password(''),plugin='mysql_native_password' where user='root';
in my case I needed to type these 3 lines:
use mysql;
update user set authentication_string=password('new_root_password'), plugin='mysql_native_password' where user='root';
flush privileges;