diff --git a/src/main/java/com/uid2/shared/attest/UidCoreClient.java b/src/main/java/com/uid2/shared/attest/UidCoreClient.java
index 75b4574b..4f090739 100644
--- a/src/main/java/com/uid2/shared/attest/UidCoreClient.java
+++ b/src/main/java/com/uid2/shared/attest/UidCoreClient.java
@@ -89,8 +89,12 @@ private InputStream internalDownload(String path) throws CloudStorageException {
                 inputStream = getWithAttest(path);
             }
             return inputStream;
+        } catch (CloudStorageException e) {
+            throw e;
         } catch (Exception e) {
-            throw new CloudStorageException("download error: " + e.getMessage(), e);
+            throw new CloudStorageException(
+                "E12: Data Download Failure - exception: " + e.getClass().getSimpleName() + 
+                ". Please visit UID2 guides for troubleshooting", e);
         }
     }
 
@@ -108,7 +112,9 @@ private InputStream getWithAttest(String path) throws IOException, AttestationRe
         HttpResponse<String> httpResponse;
         httpResponse = sendHttpRequest(path, attestationToken);
         if (httpResponse.statusCode() != 200) {
-            throw new CloudStorageException(String.format("Non-success response from core on request to %s. Status code: %d", path, httpResponse.statusCode()));
+            throw new CloudStorageException(String.format(
+                "E12: Data Download Failure - HTTP response code %d. Please visit UID2 guides for troubleshooting", 
+                httpResponse.statusCode()));
         }
         return Utils.convertHttpResponseToInputStream(httpResponse);
     }
diff --git a/src/main/java/com/uid2/shared/cloud/URLStorageWithMetadata.java b/src/main/java/com/uid2/shared/cloud/URLStorageWithMetadata.java
index ed6c00db..65ed15e3 100644
--- a/src/main/java/com/uid2/shared/cloud/URLStorageWithMetadata.java
+++ b/src/main/java/com/uid2/shared/cloud/URLStorageWithMetadata.java
@@ -48,8 +48,8 @@ public InputStream download(String cloudPath) throws CloudStorageException {
             if (responseCode >= 200 && responseCode < 300) {
                 return httpConn.getInputStream();
             } else {
-                throw new CloudStorageException("Cannot download required files, HTTP response code " + responseCode 
-                + ", please visit UID2 guides for more details");
+                throw new CloudStorageException("E12: Data Download Failure - HTTP response code " + responseCode 
+                + ". Please visit UID2 guides for troubleshooting");
             }
         }
         catch (CloudStorageException e) {
@@ -58,8 +58,8 @@ public InputStream download(String cloudPath) throws CloudStorageException {
         } 
         catch (Throwable t) {
             // Do not log the original exception as it may contain sensitive information such as the pre-signed URL
-            throw new CloudStorageException("Cannot download required files, exception: " + t.getClass().getSimpleName() +
-                ", please visit UID2 guides for more details");
+            throw new CloudStorageException("E12: Data Download Failure - exception: " + t.getClass().getSimpleName() +
+                ". Please visit UID2 guides for troubleshooting");
         }
     }
 
diff --git a/src/main/java/com/uid2/shared/vertx/CloudSyncVerticle.java b/src/main/java/com/uid2/shared/vertx/CloudSyncVerticle.java
index a06f4213..fa195ed8 100644
--- a/src/main/java/com/uid2/shared/vertx/CloudSyncVerticle.java
+++ b/src/main/java/com/uid2/shared/vertx/CloudSyncVerticle.java
@@ -400,8 +400,13 @@ private void cloudDownloadBlocking(String s3Path) throws Exception {
             
             downloadFailureTimer.record(java.time.Duration.ofMillis(cloudDownloadTimeMs));            
             // Be careful as the s3Path may contain the pre-signed S3 token, so do not log the whole path
-            LOGGER.error("download error: " + ex.getClass().getSimpleName());
-            throw new CloudStorageException("Download failed"); 
+            LOGGER.error("Cloud storage download error, exception type: " + ex.getClass().getSimpleName());
+            
+            if (ex instanceof CloudStorageException) {
+                throw (CloudStorageException) ex;
+            }
+            throw new CloudStorageException("Failed to download file from cloud storage, exception: " 
+                + ex.getClass().getSimpleName() + ", please check network connectivity and service availability"); 
         }
     }
 
diff --git a/src/test/java/com/uid2/shared/attest/UidCoreClientTest.java b/src/test/java/com/uid2/shared/attest/UidCoreClientTest.java
index e55849fa..c870cdc6 100644
--- a/src/test/java/com/uid2/shared/attest/UidCoreClientTest.java
+++ b/src/test/java/com/uid2/shared/attest/UidCoreClientTest.java
@@ -72,7 +72,7 @@ public void Download_AttestInternalFail_ExceptionThrown() throws IOException, At
         CloudStorageException result = assertThrows(CloudStorageException.class, () -> {
             uidCoreClient.download("https://download");
         });
-        String expectedExceptionMessage = "download error: AttestationResponseCode: AttestationFailure, test failure";
+        String expectedExceptionMessage = "E12: Data Download Failure - exception: AttestationResponseHandlerException. Please visit UID2 guides for troubleshooting";
         assertEquals(expectedExceptionMessage, result.getMessage());
     }
 
@@ -100,4 +100,93 @@ void getJwtReturnsCoreToken() {
         when(mockAttestationResponseHandler.getCoreJWT()).thenReturn("coreJWT");
         Assertions.assertEquals("coreJWT", this.uidCoreClient.getJWT());
     }
+
+    @Test
+    public void Download_Http403Error_LogsStatusCodeAndEndpoint() throws IOException, AttestationResponseHandlerException {
+        HttpResponse<String> mockHttpResponse = mock(HttpResponse.class);
+        when(mockHttpResponse.statusCode()).thenReturn(403);
+        when(mockHttpClient.get(eq("https://core-prod.uidapi.com/sites/refresh"), any(HashMap.class))).thenReturn(mockHttpResponse);
+
+        CloudStorageException result = assertThrows(CloudStorageException.class, () -> {
+            uidCoreClient.download("https://core-prod.uidapi.com/sites/refresh");
+        });
+
+        assertAll(
+            () -> assertTrue(result.getMessage().contains("E12: Data Download Failure"), 
+                "Should contain E12 error code"),
+            () -> assertTrue(result.getMessage().contains("HTTP response code 403"), 
+                "Should contain HTTP status code 403"),
+            () -> assertTrue(result.getMessage().contains("Please visit UID2 guides for troubleshooting"), 
+                "Should reference documentation")
+        );
+    }
+
+    @Test
+    public void Download_Http404Error_LogsStatusCode() throws IOException, AttestationResponseHandlerException {
+        HttpResponse<String> mockHttpResponse = mock(HttpResponse.class);
+        when(mockHttpResponse.statusCode()).thenReturn(404);
+        when(mockHttpClient.get(eq("https://core-prod.uidapi.com/keys/refresh"), any(HashMap.class))).thenReturn(mockHttpResponse);
+
+        CloudStorageException result = assertThrows(CloudStorageException.class, () -> {
+            uidCoreClient.download("https://core-prod.uidapi.com/keys/refresh");
+        });
+
+        assertAll(
+            () -> assertTrue(result.getMessage().contains("HTTP response code 404"), 
+                "Should contain HTTP status code 404"),
+            () -> assertTrue(result.getMessage().contains("E12: Data Download Failure"), 
+                "Should contain E12 error code")
+        );
+    }
+
+    @Test
+    public void Download_Http500Error_LogsStatusCode() throws IOException, AttestationResponseHandlerException {
+        HttpResponse<String> mockHttpResponse = mock(HttpResponse.class);
+        when(mockHttpResponse.statusCode()).thenReturn(500);
+        when(mockHttpClient.get(eq("https://core-prod.uidapi.com/salts/refresh"), any(HashMap.class))).thenReturn(mockHttpResponse);
+
+        CloudStorageException result = assertThrows(CloudStorageException.class, () -> {
+            uidCoreClient.download("https://core-prod.uidapi.com/salts/refresh");
+        });
+
+        assertAll(
+            () -> assertTrue(result.getMessage().contains("E12: Data Download Failure"), 
+                "Should contain E12 error code"),
+            () -> assertTrue(result.getMessage().contains("HTTP response code 500"), 
+                "Should contain HTTP status code 500")
+        );
+    }
+
+    @Test
+    public void Download_Http503Error_LogsStatusCode() throws IOException, AttestationResponseHandlerException {
+        HttpResponse<String> mockHttpResponse = mock(HttpResponse.class);
+        when(mockHttpResponse.statusCode()).thenReturn(503);
+        when(mockHttpClient.get(eq("https://core-integ.uidapi.com/clients/refresh"), any(HashMap.class))).thenReturn(mockHttpResponse);
+
+        CloudStorageException result = assertThrows(CloudStorageException.class, () -> {
+            uidCoreClient.download("https://core-integ.uidapi.com/clients/refresh");
+        });
+
+        assertTrue(result.getMessage().contains("HTTP response code 503"), 
+            "Should contain HTTP status code 503");
+    }
+
+    @Test
+    public void Download_NetworkError_LogsExceptionType() throws IOException, AttestationResponseHandlerException {
+        IOException networkException = new IOException("Connection timeout");
+        when(mockHttpClient.get(anyString(), any(HashMap.class))).thenThrow(networkException);
+
+        CloudStorageException result = assertThrows(CloudStorageException.class, () -> {
+            uidCoreClient.download("https://core-prod.uidapi.com/sites/refresh");
+        });
+
+        assertAll(
+            () -> assertTrue(result.getMessage().contains("E12: Data Download Failure"), 
+                "Should contain E12 error code"),
+            () -> assertTrue(result.getMessage().contains("exception: IOException"), 
+                "Should log exception type"),
+            () -> assertTrue(result.getMessage().contains("Please visit UID2 guides for troubleshooting"), 
+                "Should reference documentation")
+        );
+    }
 }