diff --git a/apis/cloudstack/src/main/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandler.java b/apis/cloudstack/src/main/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandler.java
index 8988d649a4..170f89069a 100644
--- a/apis/cloudstack/src/main/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandler.java
+++ b/apis/cloudstack/src/main/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandler.java
@@ -77,6 +77,9 @@ public class CloudStackErrorHandler implements HttpErrorHandler {
                exception = new IllegalStateException(message, exception);
             }
             break;
+         case 537:
+            exception = new IllegalStateException(message, exception);
+            break;
          }
       } finally {
          if (response.getPayload() != null)
diff --git a/apis/cloudstack/src/test/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandlerTest.java b/apis/cloudstack/src/test/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandlerTest.java
index 81f0a88239..36ea5eaacb 100644
--- a/apis/cloudstack/src/test/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandlerTest.java
+++ b/apis/cloudstack/src/test/java/org/jclouds/cloudstack/handlers/CloudStackErrorHandlerTest.java
@@ -91,6 +91,16 @@ public class CloudStackErrorHandlerTest {
       assertCodeMakes("GET", URI.create("https://cloudstack.com/foo"), 409, "", "Conflict", IllegalStateException.class);
    }
 
+   @Test void test537MakesIllegalStateException() {
+      assertCodeMakes(
+            "GET",
+            URI.create("http://10.26.26.155:8080/client/api?response=json&command=createIpForwardingRule&ipaddressid=37&startport=22&protocol=tcp"),
+            537,
+            "",
+            "{ \"createipforwardingruleresponse\" : {\"errorcode\" : 537, \"errortext\" : \"There is already firewall rule specified for the ip address id=37\"}  }",
+            IllegalStateException.class);
+   }
+
    private void assertCodeMakes(String method, URI uri, int statusCode, String message, String content,
          Class<? extends Exception> expected) {
       assertCodeMakes(method, uri, statusCode, message, "text/xml", content, expected);