Jmeter giving following error

org.apache.http.NoHttpResponseException: The target server failed to respond at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:95) at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:61) at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:254) at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:289) at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:252) at org.apache.http.impl.conn.ManagedClientConnectionImpl.receiveResponseHeader(ManagedClientConnectionImpl.java:191) at org.apache.jmeter.protocol.http.sampler.MeasuringConnectionManager$MeasuredConnection.receiveResponseHeader(MeasuringConnectionManager.java:201) at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:300) at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:127) at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:715) at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:520) at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906) at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805) at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:517) at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:331) at org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:74) at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1146) at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1135) at org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:434) at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:261) at java.lang.Thread.run(Thread.java:745)