Having issues with Certs for API on Spring 5

I’m building an API using Spring Security 5. Followed the instructions, and got an error: PKIX path building failed: unable to find valid certification path to requested target . Assuming the target is spring.security.oauth2.resourceserver.jwt.issuer-uri. So, I went into the depths of my Advanced settings for my API config and obtained the cert and added that to my JRE cacerts file. Still getting the same error. Double checked that my JRE is the one I am using, and it seems correct. Thoughts?