Unable to connect to a maria db from the datamart, have no issues connecting when using powerbi desktop, and with setting up scheduled refresh using an on-premise gateway connector with powerbi online.
Error is either "An exception occurred: 3 arguments were passed to a function which expects between 1 and 2."
or "Unexpected error" depending on if I specify the database in the datasource (which from the placeholder text should be valid).
Recently we have received feedback about problems connecting to Maria DB, and in most cases there are problems with invalid credentials. I tried to reproduce your problem but it didn't appear the same as yours. Is this a temporary problem and does the problem still exist?