After many toilsome hours, I have fixed it by altering the application.yml:

server:
  port: 9002

spring:
  kafka:
    consumer:
      auto-offset-reset: earliest
      bootstrap-servers: ${SPRING_KAFKA_BOOTSTRAP_SERVERS:localhost:29092} 
      group-id: order-consumer-group
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.springframework.kafka.support.serializer.ErrorHandlingDeserializer
      properties:
        spring.deserializer.value.delegate.class: org.springframework.kafka.support.serializer.JsonDeserializer
        spring.json.trusted.packages: com.Memorium.order_consumer.payload
        spring.json.value.default.type: com.Memorium.order_consumer.payload.Order

Just needed to change boot change bootstrap-servers to

bootstrap-servers: ${SPRING_KAFKA_BOOTSTRAP_SERVERS:localhost:29092}