Authentication Exception - 'Could not determine impl for class


I am using a COTS package based on springboot which uses a plugin mechanism for adding a custom identity manager. Hence Ive created a custom plugin which wraps the Okta authentication SDK. Its a basic implementation which effectively uses the authenticate API;

CompletableFuture authenticationResponseCompletableFuture = new CompletableFuture<>();
final AuthenticationResponse response = oktaAuthClient.authenticate(userId, password.toCharArray(),
“”, new OktaBasicAuthenticationStateHandler(oktaAuthClient,

Im getting an illegal argument exception -

java.lang.IllegalArgumentException: Could not determine impl for class: ‘com.okta.authn.sdk.resource.AuthenticationRequest’

Okta config looks ok as the management API SDK is working fine. My suspicion is possible classloader challenges as the plugin uses Springboot bean discovery etc…

Any suggestions on how to address this exception?