Trying to define an external database for session logs it does not create the mysql tables.
If we look at tomcat logs we can see
SEVERE: Call to Gatekeeper service controller failed: java.sql.SQLException: The server time zone value 'ora solare Europa occidentale' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
Look at the Mysql following link:
which has instructions on how to set a time zone in the MySQL database.
set this value in my.cnf config file
Tables are created and all logs sent to the db