There are a couple of different variables here. Are you talking about the default Portal button, in the lower right? Are you able to share a link to your site?
It looks like Data Plot Plus is set up to be invite-only, which explains the difference in button behavior. You can change this setting on the Membership page in Settings.
I see. That makes sense.
I was experimenting a lot - in order to solve the other problem
I think I break the configuration somehow - now I got errors sending magic link.
So I will create new installation and import the content and members there.
Since the login is not working (right now it’s not working on both - previously it was working on Data Plot Plus.