Signup from Universal-login does not sign user in automatically

I’m using the universal login solution with a custom UI (Branding > universal login > advanced options > login => then add custom html). Within my custom UI, I use the auth0-js package and it’s signup function.

I read in a previous answer that when using the universal login, the signup automatically logs the user in but in my case, the user is just stuck on the same page. I can see that use user was created successfully in the auth0 dashboard - my only problem is the auto login is missing :frowning: