Single Sign-On with WordPress

Hi,

I am currently building a website with Divi for a hosting business and I plan on using Chargebee to handle my billing. Chargebee offers an open source customer portal that I will have on a subdomain on a different server.

The problem is that it uses Chargebee's login page and authentication by default. They also offer a single sign-on option which I would like to use. Their documentation says I have to create a portal session with the API, but I don't know how.

I am not sure how exactly to do this with WordPress. I've searched the community forum here and the only thing I could find was to use a plugin called Auth0. I'm not sure if that will solve my problem or not. I just want my users to be able to sign into Wordpress and automatically be signed into the customer portal on the subdomain as well. Any suggestions?