MongoDB Sink Connector is not connecting to Kafka Connect and reading events from Kafka topics

I am new to MongoDB. I am trying to read events from Kafka topic through MongoDB sink connector. I configured the connector and follow the steps as per below link

After performing all steps connector is still in failed status and showing below error.
caused by {javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target}, caused by {sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target}, caused by {sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target}}]\n\tat com.mongodb.internal.connection.BaseCluster.getDescription(BaseCluster.java:182)\n\tat com.mongodb.internal.connection.SingleServerCluster.getDescription(SingleServerCluster.java:41)\n\tat com.mongodb.client.internal.MongoClientDelegate.getConnectedClusterDescription(MongoClientDelegate.java:152)\n\tat com.mongodb.client.internal.MongoClientDelegate.createClientSession(MongoClientDelegate.java:103)\n\tat com.mongodb.client.internal.MongoClientDelegate$DelegateOperationExecutor.getClientSession(MongoClientDelegate.java:284)\n\tat com.mongodb.client.internal.MongoClientDelegate$DelegateOperationExecutor.execute(MongoClientDelegate.java:208)\n\tat com.mongodb.client.internal.MongoCollectionImpl.executeBulkWrite(MongoCollectionImpl.java:476)\n\tat com.mongodb.client.internal.MongoCollectionImpl.bulkWrite(MongoCollectionImpl.java:456)\n\tat at.grahsl.kafka.connect.mongodb.MongoDbSinkTask.processSinkRecords(MongoDbSinkTask.java:148)\n\t… 16 more\n"
}
],
“type”: “sink”