diff --git a/backend/src/Squidex.Web/ApiExceptionConverter.cs b/backend/src/Squidex.Web/ApiExceptionConverter.cs
index 40691cf6e..24f3a103d 100644
--- a/backend/src/Squidex.Web/ApiExceptionConverter.cs
+++ b/backend/src/Squidex.Web/ApiExceptionConverter.cs
@@ -16,6 +16,8 @@ using Microsoft.AspNetCore.Mvc;
 using Squidex.Infrastructure;
 using Squidex.Infrastructure.Translations;
 using Squidex.Infrastructure.Validation;
+using BadHttpRequestExceptionIIS = Microsoft.AspNetCore.Server.IIS.BadHttpRequestException;
+using BadHttpRequestExceptionKestrel = Microsoft.AspNetCore.Server.Kestrel.Core.BadHttpRequestException;
 
 namespace Squidex.Web
 {
@@ -106,6 +108,12 @@ namespace Squidex.Web
                 case DecoderFallbackException _:
                     return (CreateError(400, exception.Message), true);
 
+                case BadHttpRequestExceptionIIS ex:
+                    return (CreateError(ex.StatusCode, ex.Message), true);
+
+                case BadHttpRequestExceptionKestrel ex:
+                    return (CreateError(ex.StatusCode, ex.Message), true);
+
                 default:
                     return (CreateError(500), false);
             }
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Assets/AssetsController.cs b/backend/src/Squidex/Areas/Api/Controllers/Assets/AssetsController.cs
index ab154a2d0..b2cd8b3c3 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Assets/AssetsController.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Assets/AssetsController.cs
@@ -178,7 +178,8 @@ namespace Squidex.Areas.Api.Controllers.Assets
         /// <returns>
         /// 201 => Asset created.
         /// 404 => App not found.
-        /// 400 => Asset exceeds the maximum size.
+        /// 413 => Asset exceeds the maximum upload size.
+        /// 400 => Asset request not valid.
         /// </returns>
         /// <remarks>
         /// You can only upload one file at a time. The mime type of the file is not calculated by Squidex and is required correctly.
@@ -214,7 +215,8 @@ namespace Squidex.Areas.Api.Controllers.Assets
         /// <returns>
         /// 200 => Asset updated.
         /// 404 => Asset or app not found.
-        /// 400 => Asset exceeds the maximum size.
+        /// 413 => Asset exceeds the maximum upload size.
+        /// 400 => Asset request not valid.
         /// </returns>
         /// <remarks>
         /// Use multipart request to upload an asset.
diff --git a/backend/src/Squidex/Areas/Api/Controllers/Contents/ContentsController.cs b/backend/src/Squidex/Areas/Api/Controllers/Contents/ContentsController.cs
index 813c4e160..1c8e7c8f3 100644
--- a/backend/src/Squidex/Areas/Api/Controllers/Contents/ContentsController.cs
+++ b/backend/src/Squidex/Areas/Api/Controllers/Contents/ContentsController.cs
@@ -508,7 +508,7 @@ namespace Squidex.Areas.Api.Controllers.Contents
         /// <returns>
         /// 200 => Content status changed.
         /// 404 => Content, schema or app not found.
-        /// 400 => Request is not valid.
+        /// 400 => Content request is not valid.
         /// </returns>
         /// <remarks>
         /// You can read the generated documentation for your app at /api/content/{appName}/docs.