ER_MUST_CHANGE_PASSWORD_LOGIN on Ghost blog platform

Seems that our Ghost blog platform received the following error when I tried to publish a post:

Internal server error, cannot list posts. ER_MUST_CHANGE_PASSWORD_LOGIN: Your password has expired. To log in you must change it using a client that supports expired passwords.

See screenshot below:

At first glance, I thought it was related to my own Ghost user account. Turns out it was the underlying database user.

To reset the MySQL password, run the following commands:

$MYSQL_HOME/bin/mysql -u ghost_db_user -p"oldpassword" -h localhost -P 3306 ghost_db

SET PASSWORD = PASSWORD('newpassword');