diff --git a/src/main/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxy.java b/src/main/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxy.java
index d07bc429..f2683809 100644
--- a/src/main/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxy.java
+++ b/src/main/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxy.java
@@ -572,8 +572,7 @@ public ProgressEvent<ModelT, CallbackT> done(Function<ResponseT, ProgressEvent<M
         if (e instanceof AwsServiceException) {
             AwsServiceException sdkException = (AwsServiceException) e;
             AwsErrorDetails details = sdkException.awsErrorDetails();
-            String errMsg = "Exception=[" + sdkException.getClass() + "] " + "ErrorCode=[" + details.errorCode()
-                + "],  ErrorMessage=[" + details.errorMessage() + "]";
+            String errMsg = sdkException.getMessage();
             switch (details.sdkHttpResponse().statusCode()) {
                 case HttpStatusCode.BAD_REQUEST:
                     //
diff --git a/src/test/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxyTest.java b/src/test/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxyTest.java
index b4482072..9cbf0c32 100644
--- a/src/test/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxyTest.java
+++ b/src/test/java/software/amazon/cloudformation/proxy/AmazonWebServicesClientProxyTest.java
@@ -439,7 +439,7 @@ public void badRequest() {
                 .initiate("client:createRespository", proxy.newProxy(() -> mock(ServiceClient.class)), model, context)
                 .translateToServiceRequest(m -> new CreateRequest.Builder().repoName(m.getRepoName()).build())
                 .makeServiceCall((r, c) -> {
-                    throw new BadRequestException(mock(AwsServiceException.Builder.class)) {
+                    throw new BadRequestException(new AwsServiceException(AwsServiceException.builder()) {
                         private static final long serialVersionUID = 1L;
 
                         @Override
@@ -447,10 +447,10 @@ public AwsErrorDetails awsErrorDetails() {
                             return AwsErrorDetails.builder().errorCode("BadRequest").errorMessage("Bad Parameter in request")
                                 .sdkHttpResponse(sdkHttpResponse).build();
                         }
-                    };
+                    }.toBuilder());
                 }).done(o -> ProgressEvent.success(model, context));
         assertThat(result.getStatus()).isEqualTo(OperationStatus.FAILED);
-        assertThat(result.getMessage()).contains("BadRequest");
+        assertThat(result.getMessage()).contains("Bad Parameter");
     }
 
     @Test
@@ -470,7 +470,7 @@ public void notFound() {
                 .initiate("client:createRespository", proxy.newProxy(() -> mock(ServiceClient.class)), model, context)
                 .translateToServiceRequest(m -> new CreateRequest.Builder().repoName(m.getRepoName()).build())
                 .makeServiceCall((r, c) -> {
-                    throw new NotFoundException(mock(AwsServiceException.Builder.class)) {
+                    throw new NotFoundException(new AwsServiceException(AwsServiceException.builder()) {
                         private static final long serialVersionUID = 1L;
 
                         @Override
@@ -478,10 +478,10 @@ public AwsErrorDetails awsErrorDetails() {
                             return AwsErrorDetails.builder().errorCode("NotFound").errorMessage("Repo not existing")
                                 .sdkHttpResponse(sdkHttpResponse).build();
                         }
-                    };
+                    }.toBuilder());
                 }).done(o -> ProgressEvent.success(model, context));
         assertThat(result.getStatus()).isEqualTo(OperationStatus.FAILED);
-        assertThat(result.getMessage()).contains("NotFound");
+        assertThat(result.getMessage()).contains("Repo not existing");
     }
 
     @Test
@@ -501,7 +501,7 @@ public void accessDenied() {
                 .initiate("client:createRespository", proxy.newProxy(() -> mock(ServiceClient.class)), model, context)
                 .translateToServiceRequest(m -> new CreateRequest.Builder().repoName(m.getRepoName()).build())
                 .makeServiceCall((r, c) -> {
-                    throw new AccessDenied(AwsServiceException.builder()) {
+                    throw new AccessDenied(new AwsServiceException(AwsServiceException.builder()) {
                         private static final long serialVersionUID = 1L;
 
                         @Override
@@ -509,11 +509,10 @@ public AwsErrorDetails awsErrorDetails() {
                             return AwsErrorDetails.builder().errorCode("AccessDenied: 401").errorMessage("Token Invalid")
                                 .sdkHttpResponse(sdkHttpResponse).build();
                         }
-
-                    };
+                    }.toBuilder());
                 }).done(o -> ProgressEvent.success(model, context));
         assertThat(result.getStatus()).isEqualTo(OperationStatus.FAILED);
-        assertThat(result.getMessage()).contains("AccessDenied");
+        assertThat(result.getMessage()).contains("Token Invalid");
     }
 
     @Test
diff --git a/src/test/java/software/amazon/cloudformation/proxy/End2EndCallChainTest.java b/src/test/java/software/amazon/cloudformation/proxy/End2EndCallChainTest.java
index f4fb32b7..b54ecf1f 100644
--- a/src/test/java/software/amazon/cloudformation/proxy/End2EndCallChainTest.java
+++ b/src/test/java/software/amazon/cloudformation/proxy/End2EndCallChainTest.java
@@ -107,7 +107,7 @@ public void happyCase() {
         //
         // Now reset expectation to fail with already exists
         //
-        final ExistsException exists = new ExistsException(mock(AwsServiceException.Builder.class)) {
+        final ExistsException exists = new ExistsException(new AwsServiceException(AwsServiceException.builder()) {
             private static final long serialVersionUID = 1L;
 
             @Override
@@ -115,7 +115,7 @@ public AwsErrorDetails awsErrorDetails() {
                 return AwsErrorDetails.builder().errorCode("AlreadyExists").errorMessage("Repo already exists")
                     .sdkHttpResponse(sdkHttpResponse).build();
             }
-        };
+        }.toBuilder());
         when(serviceClient.createRepository(any(CreateRequest.class))).thenThrow(exists);
         StdCallbackContext newContext = new StdCallbackContext();
         event = proxy.initiate("client:createRepository", client, model, newContext)
@@ -124,7 +124,7 @@ public AwsErrorDetails awsErrorDetails() {
             .done(r -> ProgressEvent.success(model, context));
 
         assertThat(event.getStatus()).isEqualTo(OperationStatus.FAILED);
-        assertThat(event.getMessage()).contains("AlreadyExists");
+        assertThat(event.getMessage()).contains("Repo already exists");
     }
 
     private HandlerRequest<Model, StdCallbackContext> prepareRequest(Model model) throws Exception {
@@ -196,7 +196,7 @@ public void notFound() throws Exception {
         final DescribeRequest describeRequest = new DescribeRequest.Builder().repoName(model.getRepoName()).overrideConfiguration(
             AwsRequestOverrideConfiguration.builder().credentialsProvider(StaticCredentialsProvider.create(MockCreds)).build())
             .build();
-        final NotFoundException notFound = new NotFoundException(mock(AwsServiceException.Builder.class)) {
+        final NotFoundException notFound = new NotFoundException(new AwsServiceException(AwsServiceException.builder()) {
             private static final long serialVersionUID = 1L;
 
             @Override
@@ -204,7 +204,7 @@ public AwsErrorDetails awsErrorDetails() {
                 return AwsErrorDetails.builder().errorCode("NotFound").errorMessage("Repo not existing")
                     .sdkHttpResponse(sdkHttpResponse).build();
             }
-        };
+        }.toBuilder());
         when(client.describeRepository(eq(describeRequest))).thenThrow(notFound);
 
         final SdkHttpClient httpClient = mock(SdkHttpClient.class);
@@ -221,7 +221,7 @@ public AwsErrorDetails awsErrorDetails() {
             });
         assertThat(response).isNotNull();
         assertThat(response.getStatus()).isEqualTo(OperationStatus.FAILED);
-        assertThat(response.getMessage()).contains("NotFound");
+        assertThat(response.getMessage()).contains("Repo not existing");
     }
 
     @SuppressWarnings("unchecked")
@@ -299,7 +299,7 @@ public void createHandlerAlreadyExists() throws Exception {
         final SdkHttpResponse sdkHttpResponse = mock(SdkHttpResponse.class);
         when(sdkHttpResponse.statusCode()).thenReturn(500);
 
-        final ExistsException exists = new ExistsException(mock(AwsServiceException.Builder.class)) {
+        final ExistsException exists = new ExistsException(new AwsServiceException(AwsServiceException.builder()) {
             private static final long serialVersionUID = 1L;
 
             @Override
@@ -307,7 +307,7 @@ public AwsErrorDetails awsErrorDetails() {
                 return AwsErrorDetails.builder().errorCode("AlreadyExists").errorMessage("Repo already exists")
                     .sdkHttpResponse(sdkHttpResponse).build();
             }
-        };
+        }.toBuilder());
         when(client.createRepository(eq(createRequest))).thenThrow(exists);
 
         final SdkHttpClient httpClient = mock(SdkHttpClient.class);
@@ -327,7 +327,7 @@ public AwsErrorDetails awsErrorDetails() {
         assertThat(request.getRequestData()).isNotNull();
         Model responseModel = response.getResourceModel();
         assertThat(responseModel.getRepoName()).isEqualTo("repository");
-        assertThat(response.getMessage()).contains("AlreadyExists");
+        assertThat(response.getMessage()).contains("Repo already exists");
     }
 
     @Order(30)
@@ -469,7 +469,7 @@ public void accessDenied() throws Exception {
         final DescribeRequest describeRequest = new DescribeRequest.Builder().repoName(model.getRepoName()).overrideConfiguration(
             AwsRequestOverrideConfiguration.builder().credentialsProvider(StaticCredentialsProvider.create(MockCreds)).build())
             .build();
-        final AccessDenied accessDenied = new AccessDenied(mock(AwsServiceException.Builder.class)) {
+        final AccessDenied accessDenied = new AccessDenied(new AwsServiceException(AwsServiceException.builder()) {
             private static final long serialVersionUID = 1L;
 
             @Override
@@ -478,7 +478,7 @@ public AwsErrorDetails awsErrorDetails() {
                     .sdkHttpResponse(sdkHttpResponse).build();
             }
 
-        };
+        }.toBuilder());
         when(client.describeRepository(eq(describeRequest))).thenThrow(accessDenied);
 
         final SdkHttpClient httpClient = mock(SdkHttpClient.class);
@@ -495,7 +495,7 @@ public AwsErrorDetails awsErrorDetails() {
             });
         assertThat(response).isNotNull();
         assertThat(response.getStatus()).isEqualTo(OperationStatus.FAILED);
-        assertThat(response.getMessage()).contains("AccessDenied");
+        assertThat(response.getMessage()).contains("Token Invalid");
     }
 
 }