title: WSO2 ESB 4.9.0: what means error 101500
body: <p>In a connection to a server we get errors such as:</p>
  
  <pre><code>&lt;errorCode&gt;101500&lt;/errorCode&gt;&lt;errorMessage&gt;Error in Sender&lt;/errorMessage&gt;
  </code></pre>
  
  <p>Is there a way to get more information on the cause, except from "Error in Sender"?</p>
  
  <p>Note: In the SSL transport sender I have set AllowAll for the HostnameVerifier</p>
  
  <pre><code>&lt;transportSender name="https" class="org.apache.synapse.transport.passthru.PassThroughHttpSSLSender"&gt;
      &lt;parameter name="non-blocking" locked="false"&gt;true&lt;/parameter&gt;
      &lt;parameter name="http.proxyHost" locked="false"&gt;internet.proxy&lt;/parameter&gt;
      &lt;parameter name="http.proxyPort" locked="false"&gt;8080&lt;/parameter&gt;
      &lt;parameter name="http.nonProxyHosts" locked="false"&gt;localhost&lt;/parameter&gt;
      &lt;parameter name="HostnameVerifier"&gt;AllowAll&lt;/parameter&gt;
  </code></pre>
  
  <p>Here is some more in detail log (wso2-esb-errors.log). Note that sometimes the messages are delivered correctly to the remote server. The remote server is maintained by a customer on which I have no control. </p>
  
  <pre><code>2016-08-30 05:06:51,995 [-] [HTTPS-Sender I/O dispatcher-1] ERROR TargetHandler I/O error: Received fatal alert: handshake_failure
  javax.net.ssl.SSLException: Received fatal alert: handshake_failure
          at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
          at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1666)
          at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1634)
          at sun.security.ssl.SSLEngineImpl.recvAlert(SSLEngineImpl.java:1800)
          at sun.security.ssl.SSLEngineImpl.readRecord(SSLEngineImpl.java:1083)
          at sun.security.ssl.SSLEngineImpl.readNetRecord(SSLEngineImpl.java:907)
          at sun.security.ssl.SSLEngineImpl.unwrap(SSLEngineImpl.java:781)
          at javax.net.ssl.SSLEngine.unwrap(SSLEngine.java:624)
          at org.apache.http.nio.reactor.ssl.SSLIOSession.doUnwrap(SSLIOSession.java:228)
          at org.apache.http.nio.reactor.ssl.SSLIOSession.doHandshake(SSLIOSession.java:263)
          at org.apache.http.nio.reactor.ssl.SSLIOSession.isAppInputReady(SSLIOSession.java:391)
          at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:119)
          at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:159)
          at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:338)
          at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:316)
          at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:277)
          at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:105)
          at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:586)
          at java.lang.Thread.run(Thread.java:745)
  </code></pre>