I followed this instruction for moving the site:
https://www.youtube.com/watch?v=cM9Z8aQTCvQ
I have changed the wp_config.php accordingly based on the new database I created in the live site, including: DB_Name, database username , database password.
I also changed the MySQL hostname to "mynewsite.com", which didn't get mentioned in the instruction video.
I Still have Error with database connection.
What did I do wrong!