Internal Server Error on Locale
Okay I'm all set now. Turns out it was a production environment/MySQL issue, and it's cropped up before on Digital Ocean. See Brad's fix here.

I just added

'initSQLs' =&gt; array("SET SESSION sql_mode='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';")


to my config/db.php and good to go.