UI Action not woking in Service Portal

[shanice_sims]

I'm trying to create a Service Portal for my app with my custom tables. I was able to get the form to load; however, the "sign-up" link UI Action is not working on click in the Service Portal. On Click, I receive a notification "Record Updated". The link should redirect to a new form and populate a field called course. I believe I read that UI Server Actions don't work in the SP, but I'm not sure how to replicate this action for the SP.

I've attached pictures for the UI action, form (in/out of SP), the form the action directs to in the instance, and the notification that appears once the UI Action is clicked in the portal.

Thank you for your help