MySQL 5.6 introduced password expiration, so the password on your Homestead Virtual Machine may expire at some point.
SQLSTATE[HY000]  Your password has expired. To log in you must change it using a client that supports expired passwords.
To change this you will need to log into MySQL running on Homestead in order to change your password to fix the expiry
vagrant ssh mysql -u homestead -psecret
If you try and execute most commands you will be greeted with
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
Confusingly you can’t run the ALTER USER statement until you’ve changed your password… so you need to use SET PASSWORD
SET PASSWORD = PASSWORD('new_password');