Your system is croaking (ie. cannot connect to the database) and is trying to send an email but the system email you have configured is not formatted properly. You will need to review your logs (general server logs, webserver error logs, PHP error logs, MySQL/MariaDB error logs, osTicket System Logs, Browser Console logs, etc.) for the reason why osTicket cannot connect to the database. Once you fix that you can then update your system emails.