diff --git a/interface/src/framework/system/UploadFileForm.tsx b/interface/src/framework/system/UploadFileForm.tsx
index 4414be0fb..750808dd9 100644
--- a/interface/src/framework/system/UploadFileForm.tsx
+++ b/interface/src/framework/system/UploadFileForm.tsx
@@ -53,8 +53,10 @@ const UploadFileForm: FC = () => {
     await sendUpload(files[0]).catch((err) => {
       if (err.message === 'The user aborted a request') {
         toast.warning(LL.UPLOAD() + ' ' + LL.ABORTED());
+      } else if (err.message === 'Network Error') {
+        toast.warning('Invalid file extension');
       } else {
-        toast.warning(err.message);
+        toast.error(err.message);
       }
     });
   };
diff --git a/lib/framework/UploadFileService.cpp b/lib/framework/UploadFileService.cpp
index d06427ade..8637d45be 100644
--- a/lib/framework/UploadFileService.cpp
+++ b/lib/framework/UploadFileService.cpp
@@ -42,7 +42,9 @@ void UploadFileService::handleUpload(AsyncWebServerRequest * request, const Stri
             return;
         } else {
             md5[0] = '\0';
-            return; // unsupported file type
+            handleError(request, 406); // Not Acceptable - unsupported file type
+            request->client()->abort();
+            return;
         }
 
         if (is_firmware) {
@@ -122,18 +124,17 @@ void UploadFileService::uploadComplete(AsyncWebServerRequest * request) {
         request->send(response);
         return;
     }
+
     if (strlen(md5) == 32) {
         auto *     response = new AsyncJsonResponse(false, 256);
         JsonObject root     = response->getRoot();
         root["md5"]         = md5;
         response->setLength();
         request->send(response);
-        // AsyncWebServerResponse * response = request->beginResponse(201, "text/plain", md5); // created
-        // request->send(response);
         return;
     }
 
-    handleError(request, 403); // send the forbidden response
+    handleError(request, 406); // send the forbidden response
 }
 
 void UploadFileService::handleError(AsyncWebServerRequest * request, int code) {
@@ -143,9 +144,9 @@ void UploadFileService::handleError(AsyncWebServerRequest * request, int code) {
     }
 
     // send the error code to the client and record the error code in the temp object
-    request->_tempObject              = new int(code);
     AsyncWebServerResponse * response = request->beginResponse(code);
     request->send(response);
+    handleEarlyDisconnect();
 }
 
 void UploadFileService::handleEarlyDisconnect() {