How to have React Front-end secured by Okta make REST Call to Grails 2.4.5 Back-End secured by Okta?

Hello,

I am trying to have a React Front-End secured with Okta (different Okta Client Id than Grails 2.4.5 Back-End, but same authorization server) make a simple REST Call to a Grails 2.4.5 app secured with Okta (Different Okta Client Id than React Front-End, but same authorization Server).

The Grails 2.4.5 Grails Back-End App is secured with Okta through a custom Grails plugin that handles Okta.

I am able to see on the back-end the Okta secured APIs through the browser, most likely because Okta is implemented throughout the network, however even programmatically, I am not sure what Okta parameters to add to even test the Rest endpoints on Postman or just with a curl within IntelliJ.

The user consent isn’t required in the Okta settings and the Log in is initiated by “App only”.

I need help understanding the entire Okta process to have a React Okta secured Front-End make a simple Rest Call to a Grails 2.4.5 Back-End. An example will be nice to see.

I have looked at the Java examples, but so far it hasn’t helped me as much.

Thank you.