Is SSO and Silent Login possible with Classic experience?

Hi Auth0 community.

I am new to Auth0 and I recently followed Auth0 Vue SDK Quickstarts: Login and created a sample app. It works beautifully.

My goal is to give the login window a custom feel (with some amount of CSS etc.), so I browsed around for solutions. I’ve found a setting under branding. (Note that I currently do not have custom domain (still trying things out)).

I try enabling the setting at Branding > Universal Login > Customize Login Page.

Instantly I see the login window looks different and can surely customize it easily.

However, I encountered the following problem: login in is fine, but once I refresh the page after logging in, the user is also logged out as well. This is not happening before I enable the above setting.

Did I miss any configs in the code or on Auth0 dashboard that I need to get it working? I’ve kept everything the same as in the tutorial and in default on Auth0 dashboard (other than toggling on the customize part).

Any help would be great!

Many thanks.