Can we use Multiple Users at a time for one service in wso2 Esb

Question

my client sending me single request that time my proxy processing the response well whenever number of clients increasing my proxy went error means same service hit by number of client request with HTTP request my error like this

 PassThroughHttpListener System may be unstable: HTTP ListeningIOReactor encountered a runtime exception : null
java.lang.NullPointerException
   at org.apache.synapse.transport.passthru.SourceResponse.start(SourceResponse.java:83)
   at org.apache.synapse.transport.passthru.SourceHandler.responseReady(SourceHandler.java:184)
   at org.apache.http.impl.nio.DefaultNHttpServerConnection.produceOutput(DefaultNHttpServerConnection.java:223)
   at org.apache.http.impl.nio.DefaultServerIOEventDispatch.outputReady(DefaultServerIOEventDispatch.java:161)
   at org.apache.http.impl.nio.reactor.BaseIOReactor.writable(BaseIOReactor.java:179)
   at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:344)
   at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:318)
   at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:278)
   at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
   at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:542)
   at java.lang.Thread.run(Thread.java:679)
 Can we handle number of clients in wso2esb for that i need to set any HTTP NOnBlocking Property