Okta server side token validation in OIDC

I am using Spring boot as my resource server and react as my SPA. I made an OIDC app in okta and getting the access token from the OKTA. Then, I am sending this token my spring boot resource server but there I am getting Unauthorized.
My Spring boot config.

okta.oauth2.issuer= https://navi-2020.okta.com

My React config:
const config = {
issuer: ‘https://navi-2020.okta.com’,
redirectUri: window.location.origin + ‘/implicit/callback’,
clientId: “0oa57fbt3r5I638u94x6”,
pkce: true

My app in okta:

This is the error i get everytime :slight_smile:
Bearer error=“invalid_token”, error_description=“An error occurred while attempting to decode the Jwt: Invalid token”, error_uri=“https://tools.ietf.org/html/rfc6750#section-3.1

I have used Okta-spring-boot-starter as my dependency.

It is working fine with this server:(with all corresponding config)

But creating problem when i am doing the above mentioned approach.
Please help

Hi @Shubham6541

Access tokens created by org authorization server can not be verified locally through a JWT verifier as the signing keys for them are not present due to RFC restrictions. The only possibility to validate the tokens is by using the /introspect endpoint.

Thanx, It really helped.

how to validate token using /introspect endpoint in spring boot application , if i don’t have client_secret.
please help.
Thank you.