I’ve gone through the documentation of Bareos and there are a few more settings you’ll need to add to your code. Here is the exact page needed - https://docs.bareos.org/TasksAndConcepts/CatalogMaintenance.html
You’ll need to specify the port as a first.
Additionally, since you are trying to connect from another droplet, you’ll need to allow connections to it from your DB droplet. For that, you can use iptables.
The following rule executed on your DB droplet
iptables -A INPUT -i eth0 -p tcp -m tcp --dport 3306 -j ACCEPT
will allow connections to port 3306, where your MySQL should be listening to. This will allow connections from all IP addresses not only your other droplet. As such, it’s not highly recommended to use it. It’s quite better to use
iptables -I INPUT -p tcp -s 0.0.0.0/0 --dport 3306 -j DROP
iptables -I INPUT -p udp -s 0.0.0.0/0 --dport 3306 -j DROP
You’ll need to replace *0.0.0.0/0 with the actual IP address of the droplet *your application is on.
To summarize, you’ll need to edit your configuration file according to the documentation in order to at least specify port. As soon as this has been done, you’ll need to allow access from your DB droplet to your Application droplet to the MySQL/MariaDB instance.