This either means that the username and password information in your wp-config.php
file is incorrect or that contact with the database server at db-mysql-sgp1-lnchub-ecosystem-do-user-3666106-0.a.db.ondigitalocean.com:25060
could not be established. This could mean your host’s database server is down.
If you are unsure what these terms mean you should probably contact your host. If you still need help you can always visit the WordPress support forums.