How to connect the database on a Synology Diskstation

I have a synology disk station running dsm6.
on it is a webserver which is running invoiceplane,
I am able to access the setup page from my browser and can get to the screen that asks for the host name, user name, password and database name.

I have on the synology running mariadb and phpmy admin.
I have created a new database and have checked from phpmyadmin the stats so i can see it is up and running.

When I enter the database name into the database name field it says it cannot find the database.
I have done much searching, pretty much a day in fact, on this site, the wiki you tube google, and have not managed to get anywhere.

I know very little about databases and need some help.
Please can someone reach out.
you can find me on hangouts

For the mySQL installation, did you follow any instruction? I can see there is one on Synology website but not sure if it may help

Other than that, IP or account permission may be the issue, have you checked that all good?