After fixing AXIS2-5374 it is mandatory to send "SOAPAction" header when sending a SOAP 1.1 message ( "text.xml") . 
diff --git a/modules/testkit/src/main/java/org/apache/axis2/transport/testkit/http/JavaNetClient.java b/modules/testkit/src/main/java/org/apache/axis2/transport/testkit/http/JavaNetClient.java
index 49d21dc..fcafc12 100644
--- a/modules/testkit/src/main/java/org/apache/axis2/transport/testkit/http/JavaNetClient.java
+++ b/modules/testkit/src/main/java/org/apache/axis2/transport/testkit/http/JavaNetClient.java
@@ -60,6 +60,9 @@
             connection.setDoOutput(true);
             connection.setDoInput(true);
             connection.setRequestProperty("Content-Type", contentType.toString());
+            if(contentType.getBaseType().equals("text/xml")){
+                connection.setRequestProperty("SOAPAction", "");
+            }
             OutputStream out = connection.getOutputStream();
             out.write(message);
             out.close();