Hello @hemanth_ch ,
When synchronizer pods have connection issues to Cassandra, they will fail their health probe leading newer Message Processor pods not able to start due to lack of contracts, you can review the logs on Cloud Logging
resource.type="k8s_container"
resource.labels.container_name="apigee-synchronizer"
(jsonPayload.className="com.apigee.probe.ProbeAPI" OR jsonPayload.className="com.apigee.probe.ProbeServiceImpl")
You can check the status of the Cassandra nodes using nodetool status, is very important verify that Cassandra cluster was able to accept new connections.
I recommend create a support ticket to have more assistance.