Camel service call giving 400 error - apache-camel

Question

I am using Camel serviceCall to call my eureka VIP. The host and port are resolved as expected. But the response is 400 and an error is thrown. My serviceCall looks like something below:
from("direct:servicecall")
.setBody().constant(null)
.setHeader(Exchange.HTTP_METHOD, constant(HttpMethods.GET))
.serviceCall().name("eureka_vip_name")
.expression()
.simple("http4:${header.CamelServiceCallServiceHost}:${header.CamelServiceCallServicePort}"
+ "service call path and parameters")
.end()
Adding the error logs:
org.apache.camel.http.common.HttpOperationFailedException: HTTP operation failed invoking http://172.31.20.241:8080/<------url path and parameteres------> with statusCode: 400
at org.apache.camel.component.http4.HttpProducer.populateHttpOperationFailedException(HttpProducer.java:312) ~[camel-http4-2.20.1.jar!/:2.20.1]
at org.apache.camel.component.http4.HttpProducer.process(HttpProducer.java:207) ~[camel-http4-2.20.1.jar!/:2.20.1]
at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.processor.SendDynamicProcessor$1.doInAsyncProducer(SendDynamicProcessor.java:132) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.impl.ProducerCache.doInAsyncProducer(ProducerCache.java:445) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.processor.SendDynamicProcessor.process(SendDynamicProcessor.java:127) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.impl.cloud.DefaultServiceCallProcessor.execute(DefaultServiceCallProcessor.java:184) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.impl.cloud.DefaultServiceCallProcessor.lambda$process$0(DefaultServiceCallProcessor.java:164) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.spring.cloud.CamelSpringCloudServiceLoadBalancer.lambda$process$0(CamelSpringCloudServiceLoadBalancer.java:66) ~[camel-spring-cloud-2.20.1.jar!/:2.20.1]
at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:98) ~[spring-cloud-netflix-core-1.3.4.RELEASE.jar!/:1.3.4.RELEASE]
at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.execute(RibbonLoadBalancerClient.java:80) ~[spring-cloud-netflix-core-1.3.4.RELEASE.jar!/:1.3.4.RELEASE]
at org.apache.camel.spring.cloud.CamelSpringCloudServiceLoadBalancer.process(CamelSpringCloudServiceLoadBalancer.java:66) ~[camel-spring-cloud-2.20.1.jar!/:2.20.1]
at org.apache.camel.impl.cloud.DefaultServiceCallProcessor.process(DefaultServiceCallProcessor.java:164) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:76) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.processor.RedeliveryErrorHandler$AsyncRedeliveryTask.call(RedeliveryErrorHandler.java:203) ~[camel-core-2.20.1.jar!/:2.20.1]
at org.apache.camel.processor.RedeliveryErrorHandler$AsyncRedeliveryTask.call(RedeliveryErrorHandler.java:171) ~[camel-core-2.20.1.jar!/:2.20.1]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_161]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) ~[?:1.8.0_161]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) ~[?:1.8.0_161]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_161]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_161]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_161]
I tried hitting the same url using from postMan (chrome extension): When hitting from postMan, i used the ec2 instance DNS name as host and it gives me the expected response ie, 200 OK with the expected body as result.