Data Studio: Track failed logins

i am using google analytics. i want to analyse the login form and want to know how many users fail. if the login fails, the user returns to the login form. if the login is successful, the user is taken to the target page. the target page can be different.

the metric is unique events. the filters are: – page is login.html – event action is form – event label is submit – second page is login.html

i am not sure if the unique events is the right the metric and if second page is the right filter.