This depends on the type of campaign: with flexible campaigns, every euro is paid out, even if the first funding target has not been reached.
For campaigns based on the "all-or-nothing principle", no payment is made if the minimum amount has not been reached and the term has ended. This means that the funds announced are not collected from the supporters and no financial obligations arise for the starters. Your project is therefore only "successful" if the goal is reached.
You can tell whether a campaign is eligible for payment by the dark dot at the top of the funding bar on the project page.