Ahhh, okay, then you should have the following error in the log too:
ERROR metabase.driver :: Failed to connect to database: java.sql.SQLException: Unable to load authentication plugin 'caching_sha2_password'.
Currently MySQL 8’s new default authentication is not supported by a lot of clients, so until that time, you would need to use the old mysql_native_password method.
There are many ways to change authentication method:
https://stackoverflow.com/questions/49194719/authentication-plugin-caching-sha2-password-cannot-be-loaded
For reference, since Metabase from 0.32 uses MariaDB Connector/J:
https://mariadb.com/kb/en/library/authentication-plugin-sha-256/