diff --git a/src/Squidex/Areas/Api/Config/OpenApi/ErrorDtoProcessor.cs b/src/Squidex/Areas/Api/Config/OpenApi/ErrorDtoProcessor.cs
index 8a1dabcc0..15c6322d0 100644
--- a/src/Squidex/Areas/Api/Config/OpenApi/ErrorDtoProcessor.cs
+++ b/src/Squidex/Areas/Api/Config/OpenApi/ErrorDtoProcessor.cs
@@ -7,6 +7,7 @@
 
 using System;
 using System.Linq;
+using Namotion.Reflection;
 using NJsonSchema;
 using NSwag;
 using NSwag.Generation.Processors;
@@ -61,9 +62,9 @@ namespace Squidex.Areas.Api.Config.OpenApi
 
         private JsonSchema GetErrorSchema(DocumentProcessorContext context)
         {
-            var errorType = typeof(ErrorDto);
+            var errorType = typeof(ErrorDto).ToContextualType();
 
-            return context.SchemaGenerator.Generate(errorType);
+            return context.SchemaGenerator.GenerateWithReference<JsonSchema>(errorType, context.SchemaResolver);
         }
     }
 }
diff --git a/src/Squidex/Areas/Api/Controllers/Schemas/Models/CreateSchemaDto.cs b/src/Squidex/Areas/Api/Controllers/Schemas/Models/CreateSchemaDto.cs
index 8f969a4bb..fa088af3b 100644
--- a/src/Squidex/Areas/Api/Controllers/Schemas/Models/CreateSchemaDto.cs
+++ b/src/Squidex/Areas/Api/Controllers/Schemas/Models/CreateSchemaDto.cs
@@ -10,7 +10,7 @@ using Squidex.Domain.Apps.Entities.Schemas.Commands;
 
 namespace Squidex.Areas.Api.Controllers.Schemas.Models
 {
-    public sealed class CreateSchemaDto : UpsertDto
+    public sealed class CreateSchemaDto : UpsertSchemaDto
     {
         /// <summary>
         /// The name of the schema.
diff --git a/src/Squidex/Areas/Api/Controllers/Schemas/Models/SynchronizeSchemaDto.cs b/src/Squidex/Areas/Api/Controllers/Schemas/Models/SynchronizeSchemaDto.cs
index e2595140a..07118f2ae 100644
--- a/src/Squidex/Areas/Api/Controllers/Schemas/Models/SynchronizeSchemaDto.cs
+++ b/src/Squidex/Areas/Api/Controllers/Schemas/Models/SynchronizeSchemaDto.cs
@@ -9,7 +9,7 @@ using Squidex.Domain.Apps.Entities.Schemas.Commands;
 
 namespace Squidex.Areas.Api.Controllers.Schemas.Models
 {
-    public sealed class SynchronizeSchemaDto : UpsertDto
+    public sealed class SynchronizeSchemaDto : UpsertSchemaDto
     {
         /// <summary>
         /// True, when fields should not be deleted.
diff --git a/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertDto.cs b/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs
similarity index 98%
rename from src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertDto.cs
rename to src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs
index 7c3032b2e..cd753bc9e 100644
--- a/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertDto.cs
+++ b/src/Squidex/Areas/Api/Controllers/Schemas/Models/UpsertSchemaDto.cs
@@ -12,7 +12,7 @@ using Squidex.Infrastructure.Reflection;
 
 namespace Squidex.Areas.Api.Controllers.Schemas.Models
 {
-    public abstract class UpsertDto
+    public abstract class UpsertSchemaDto
     {
         /// <summary>
         /// The optional properties.
@@ -44,7 +44,7 @@ namespace Squidex.Areas.Api.Controllers.Schemas.Models
         /// </summary>
         public bool IsPublished { get; set; }
 
-        public static TCommand ToCommand<TCommand, TDto>(TDto dto, TCommand command) where TCommand : UpsertCommand where TDto : UpsertDto
+        public static TCommand ToCommand<TCommand, TDto>(TDto dto, TCommand command) where TCommand : UpsertCommand where TDto : UpsertSchemaDto
         {
             SimpleMapper.Map(dto, command);