diff --git a/common/src/main/java/org/opensearch/ml/common/MLCommonsClassLoader.java b/common/src/main/java/org/opensearch/ml/common/MLCommonsClassLoader.java
index efe6e2c39d..8f3e537e68 100644
--- a/common/src/main/java/org/opensearch/ml/common/MLCommonsClassLoader.java
+++ b/common/src/main/java/org/opensearch/ml/common/MLCommonsClassLoader.java
@@ -259,6 +259,8 @@ private static <T, S> S init(Map<T, Class<?>> map, T type,
             Throwable cause = e.getCause();
             if (cause instanceof MLException) {
                 throw (MLException)cause;
+	    } else if (cause instanceof IllegalArgumentException) {
+                throw (IllegalArgumentException) cause;
             } else {
                 log.error("Failed to init instance for type " + type, e);
                 return null;
diff --git a/common/src/main/java/org/opensearch/ml/common/connector/Connector.java b/common/src/main/java/org/opensearch/ml/common/connector/Connector.java
index 70b180115e..81278ceb89 100644
--- a/common/src/main/java/org/opensearch/ml/common/connector/Connector.java
+++ b/common/src/main/java/org/opensearch/ml/common/connector/Connector.java
@@ -88,13 +88,21 @@ default void validatePayload(String payload) {
     }
 
     static Connector fromStream(StreamInput in) throws IOException {
-        String connectorProtocol = in.readString();
-        return MLCommonsClassLoader.initConnector(connectorProtocol, new Object[]{connectorProtocol, in}, String.class, StreamInput.class);
+        try {
+            String connectorProtocol = in.readString();
+            return MLCommonsClassLoader.initConnector(connectorProtocol, new Object[]{connectorProtocol, in}, String.class, StreamInput.class);
+        } catch (IllegalArgumentException illegalArgumentException) {
+            throw illegalArgumentException;
+        }
     }
 
     static Connector createConnector(XContentBuilder builder, String connectorProtocol) throws IOException {
-        String jsonStr = builder.toString();
-        return createConnector(jsonStr, connectorProtocol);
+        try {
+            String jsonStr = builder.toString();
+            return createConnector(jsonStr, connectorProtocol);
+        } catch (IllegalArgumentException illegalArgumentException) {
+            throw illegalArgumentException;
+        }
     }
 
     static Connector createConnector(XContentParser parser) throws IOException {
@@ -118,7 +126,12 @@ private static Connector createConnector(String jsonStr, String connectorProtoco
                 throw new IllegalArgumentException("connector protocol is null");
             }
             return MLCommonsClassLoader.initConnector(connectorProtocol, new Object[]{connectorProtocol, connectorParser}, String.class, XContentParser.class);
-        }
+        } catch (Exception ex) {
+            if (ex instanceof IllegalArgumentException) {
+                throw ex;
+            }
+            return null;
+	    }
     }
 
     default void validateConnectorURL(List<String> urlRegexes) {
diff --git a/plugin/src/main/java/org/opensearch/ml/action/connector/GetConnectorTransportAction.java b/plugin/src/main/java/org/opensearch/ml/action/connector/GetConnectorTransportAction.java
index 8a1a7368fe..841a17ea65 100644
--- a/plugin/src/main/java/org/opensearch/ml/action/connector/GetConnectorTransportAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/action/connector/GetConnectorTransportAction.java
@@ -23,7 +23,6 @@
 import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.index.IndexNotFoundException;
 import org.opensearch.ml.common.connector.Connector;
-import org.opensearch.ml.common.exception.MLResourceNotFoundException;
 import org.opensearch.ml.common.exception.MLValidationException;
 import org.opensearch.ml.common.transport.connector.MLConnectorGetAction;
 import org.opensearch.ml.common.transport.connector.MLConnectorGetRequest;
@@ -92,7 +91,8 @@ protected void doExecute(Task task, ActionRequest request, ActionListener<MLConn
                 }
             }, e -> {
                 if (e instanceof IndexNotFoundException) {
-                    actionListener.onFailure(new MLResourceNotFoundException("Fail to find connector"));
+                    log.error("Failed to get connector index", e);
+                    actionListener.onFailure(new IllegalArgumentException("Fail to find connector"));
                 } else {
                     log.error("Failed to get ML connector " + connectorId, e);
                     actionListener.onFailure(e);
diff --git a/plugin/src/main/java/org/opensearch/ml/rest/RestMLCreateConnectorAction.java b/plugin/src/main/java/org/opensearch/ml/rest/RestMLCreateConnectorAction.java
index 662e635505..6f004296df 100644
--- a/plugin/src/main/java/org/opensearch/ml/rest/RestMLCreateConnectorAction.java
+++ b/plugin/src/main/java/org/opensearch/ml/rest/RestMLCreateConnectorAction.java
@@ -56,9 +56,6 @@ public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client
      */
     @VisibleForTesting
     MLCreateConnectorRequest getRequest(RestRequest request) throws IOException {
-        if (!request.hasContent()) {
-            throw new IOException("Create Connector request has empty body");
-        }
         XContentParser parser = request.contentParser();
         ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
         MLCreateConnectorInput mlCreateConnectorInput = MLCreateConnectorInput.parse(parser);
diff --git a/plugin/src/test/java/org/opensearch/ml/rest/RestMLCreateConnectorActionTests.java b/plugin/src/test/java/org/opensearch/ml/rest/RestMLCreateConnectorActionTests.java
index 36bb59a96a..8ec9f103f8 100644
--- a/plugin/src/test/java/org/opensearch/ml/rest/RestMLCreateConnectorActionTests.java
+++ b/plugin/src/test/java/org/opensearch/ml/rest/RestMLCreateConnectorActionTests.java
@@ -25,6 +25,7 @@
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
 import org.opensearch.core.action.ActionListener;
+import org.opensearch.OpenSearchParseException;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.core.common.Strings;
@@ -113,8 +114,8 @@ public void testPrepareRequest() throws Exception {
     }
 
     public void testPrepareRequest_EmptyContent() throws Exception {
-        thrown.expect(IOException.class);
-        thrown.expectMessage("Create Connector request has empty body");
+        thrown.expect(OpenSearchParseException.class);
+        thrown.expectMessage("request body is required");
         Map<String, String> params = new HashMap<>();
         RestRequest request = new FakeRestRequest.Builder(NamedXContentRegistry.EMPTY).withParams(params).build();