Confluent Platform Deployment in GKE

Hi I have installed confluent platform on GKE using the confluent operator. I have all all the loadbalancers as internal and am using the NO-DNS way to connect to the cluster running on GKE cluster.
When I use the kafka scripts such as console consumer or producer to connect, I am able to connect, produce and consume data from the cluster.
But when I use my spring boot app to connect to the cluster I get the following error -

2021-03-17 11:31:13.350 WARN 10171 — [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient : [Consumer clientId=consumer-demo-drecord-csr-group-1, groupId=demo-drecord-csr-group] Connection to node -1 ( terminated during authentication. This may happen due to any of the following reasons: (1) Authentication failed due to invalid credentials with brokers older than 1.0.0, (2) Firewall blocking Kafka TLS traffic (eg it m
ay only allow HTTPS traffic), (3) Transient network issue.

And I am unable to send or receive messages through the app. Any help is deeply appreciated.